MEANS AND METHODS FOR DIAGNOSING PANCREATIC CANCER
The present invention pertains to the field of cancer diagnosis. Specifically, it relates to a method for diagnosing pancreas cancer in a subject comprising the steps of determining in a sample of a subject suspected to suffer from pancreas cancer the amount of at least one biomarker selected from the biomarkers shown in Table 1 and comparing the said amount of the at least one biomarker with a reference, whereby pancreas cancer is to be diagnosed. The present invention also contemplates a method for identifying whether a subject is in need of a pancreas cancer therapy comprising the steps of the aforementioned methods and the further step of identifying a subject in need of a pancreas cancer therapy if said subject is to be diagnosed to suffer from pancreas cancer. Contemplated are, furthermore, diagnostic devices and kits for carrying out said methods.
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This application is a divisional of U.S. patent application Ser. No. 15/387,233, filed Dec. 21, 2016, which is a divisional of U.S. patent application Ser. No. 13/576,912, filed Oct. 4, 2012, now U.S. Pat. No. 9,551,035, which is the U.S. National Phase of International Patent Application No. PCT/EP2011/052182, filed Feb. 15, 2011, which claims priority from European Patent Application No. 10001596.5, filed Feb. 17, 2010. The contents of these applications are incorporated herein by reference in their entirety.
The present invention pertains to the field of cancer diagnosis. Specifically, it relates to a method for diagnosing pancreas cancer in a subject comprising the steps of determining in a sample of a subject suspected to suffer from pancreas cancer the amount of at least one biomarker selected from the biomarkers shown in Table 1 and comparing the said amount of the at least one biomarker with a reference, whereby pancreas cancer is to be diagnosed. The present invention also contemplates a method for identifying whether a subject is in need of a pancreas cancer therapy comprising the steps of the aforementioned methods and the further step of identifying a subject in need of a pancreas cancer therapy if said subject is to be diagnosed to suffer from pancreas cancer. Contemplated are, furthermore, diagnostic devices and kits for carrying out said methods.
Patients with carcinoma of the exocrine pancreas (adenocarcinoma) have a poor prognosis with a five-year survival rate of <5% and a median survival of 4-6 months (Jemal et al. 2009, CA Cancer J Clin 59(4): 225-249). Even after surgical intervention, the five-year survival rate is between 15% and 40% (Goggins 2005, Clinical Oncology 23(20): 4524-4531). The nonspecific or apparently absent early clinical features make pancreatic cancer a silent and devastating cancer for which there is currently no screening method for early detection. Current methods for diagnosing pancreatic cancer are rather ineffective at identifying smaller potentially curable lesions. Sensitive and specific biomarkers are needed to improve the early diagnosis.
At present, the carbohydrate antigen CA l9.9 is the only commercially available biomarker for pancreatic cancer. CA 19.9 is a tumor-associated antigen which has been originally isolated from a human colon cancer cell line. It is present on gangliosides in tissues and carried by glycoproteins in serum. The oligosaccharide which carries the CA 19.9 antigen is related to sialylated Lewis A blood group antigen. Lewis A antigen must be present before CA 19.9 can be expressed. CA 19.9 is synthesized by normal cells in pancreatic and bile ducts, gastric and colonic mucosa, bronchial and salivary glands, endometrium, and prostate.
However, the sensitivity of CA 19.9 in asymptomatic patients is low. Serum levels are elevated in less than 30% of patients with stage 1 cancers. Moreover, elevated CA 19.9 levels are not specific for pancreatic cancer but are elevated in other benign and malignant disorders.
Recent efforts focused on MIC-1 (macrophage inhibitory cytokine-1) as a serum biomarker. However, MIC-1 turned out to be comparable to CA19.9 with respect to sensitivity and specificity (Goggins, loc. cit.).
Genetic biomarkers such as mutations in K-ras and TP53 have been also identified as potential biomarkers for pancreatic cancer. However, the wide spread application of such biomarkers depends on the accuracy of the detection methods for the individual mutations which are rather inconvenient at present (Goggins, loc. cit.).
Therefore, there is still a need for a more reliable biomarker for diagnosing pancreatic cancer. In light of the severe consequences of the disease and the unspecific clinical symptoms at the beginning of the disease, such a biomarker could strengthen diagnostic and therapeutic approaches against pancreatic cancer.
Thus, the present invention relates to a method for diagnosing pancreas cancer in a subject comprising the steps of:
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- (a) determining in a sample of a subject suspected to suffer from pancreas cancer the amount of at least one biomarker selected from the biomarkers shown in Table 1; and
- (b) comparing the said amount of the at least one biomarker with a reference, whereby pancreas cancer is to be diagnosed.
The term “diagnosing” as used herein means assessing whether a subject suffers from pancreatic cancer. As will be understood by those skilled in the art, such an assessment is usually not intended to be correct for all (i.e. 100%) of the subjects to be identified. The term, however, requires that a statistically significant portion of subjects can be identified (e.g. a cohort in a cohort study). Whether a portion is statistically significant can be determined without further ado by the person skilled in the art using various well known statistic evaluation tools, e.g., determination of confidence intervals, p-value determination, Student's t-test, Mann-Whitney test etc. Details are found in Dowdy and Wearden, Statistics for Research, John Wiley & Sons, New York 1983. Preferred confidence intervals are at least 90%, at least 95%, at east 97%, at least 98% or at least 99 %. The p-values are, preferably, 0.1, 0.05, 0.01, 0.005, or 0.0001. More preferably, at least 60%, at least 70%, at least 80% or at least 90% of the subjects of a population can be properly identified by the method of the present invention. Diagnosing according to the present invention includes applications of the method in monitoring, confirmation, and subclassification of the relevant disease or its symptoms.
The term “pancreatic cancer” as used herein refers to cancer which is derived from pancreatic cells. Preferably, pancreatic cancer as used herein is pancreatic adenocarcinoma. The symptoms and implications accompanying pancreatic cancer are well known from standard text books of medicine such as Stedmen or Pschyrembl.
The term “subject” as used herein relates to animals, preferably mammals, and, more preferably, humans. Preferably, the method of the present invention will be applied for subjects suspected to either suffer from pancreatic cancer in light of clinically apparent symptoms or subjects suspected to suffer from cancer due to a potential increased predisposition. The latter subjects may be subjects suffering from chronic pancreatitis, subjects with a familiar background (i.e. subjects from families where family members suffered already from pancreatic cancer) or subjects with genetic mutations influencing pancreatic cancer, e.g., Peutz-Jeghers syndrome.
The term “biomarker” as used herein refers to a polypeptide as shown in Table 1 or a fragment or variant of such a polypeptide being associated to the presence or absence of pancreatic cancer to the same extent as the well known polypeptides recited in Table 1. The polypeptide biomarkers listed in Table 1, preferably, encompass the polypeptides referred to by public Uri Prot Accession numbers as well as variants of said polypeptides having essentially the same immunological and/or biological properties. Variants include polypeptides differ in their amino acid sequence due to the presence of conservative amino acid substitutions. Preferably, such variants have an amino acid sequence being at least 70%, at least 80%, at least 90%, at least 95%, at least 98% or at least 99% identical to the amino acid sequences of the aforementioned specific polypeptides. Variants may be allelic variants, splice variants or any other species specific homologs, paralogs, or orthologs. Preferably, the percent identity can be determined by the algorithms of Needleman and Wunsch or Smith and Waterman. To carry out the sequence alignments, the program PileUp (J. Mol. Evolution., 25, 351-360, 1987, Higgins et al., CABIOS, 5 1989: 151-153) or the programs Gap and BestFit (Needleman 1970, J. Mol. Biol. 48; 443-453 and Smith 1981, Adv. Appl. Math. 2; 482-489), which are part of the GCG software packet (Genetics Computer Group, 575 Science Drive, Madison, Wisconsin, USA 53711, Version 1991), are preferably to be used. The sequence identity values recited above in percent (%) are to be determined, preferably, using the program GAP over the entire sequence region with the following settings: Gap Weight: 50, Length Weight: 3, Average Match: 10.000 and Average Mismatch: 0.000, which, unless otherwise specified, shall always be used as standard settings for sequence alignments.
In a preferred embodiment of the method of the present invention, said at least one biomarker is selected from the biomarkers shown in Tables 2a or 2b and wherein the subject is a female. In another preferred embodiment of the method of the present invention, said at least one biomarker is selected from the biomarkers shown in Tables 3a or 3b and wherein said subject is a male.
The term “sample” refers to a sample of a body fluid, to a sample of separated cells or to a sample from a tissue or an organ. Samples of body fluids can be obtained by well known techniques and include, preferably, samples of blood, plasma, serum, pancreatic juice, or more preferably, samples of urine. Tissue or organ samples may be obtained from any tissue or organ by, e.g., biopsy. Separated cells may be obtained from the body fluids or the tissues or organs by separating techniques such as centrifugation or cell sorting. Preferably, cell-, tissue- or organ samples are obtained from those cells, tissues or organs which express or produce the peptides referred to herein.
Determining the amount of the polypeptide biomarkers referred to in this specification relates to measuring the amount or concentration, preferably semi-quantitatively or quantitatively. Measuring can be done directly or indirectly. Direct measuring relates to measuring the amount or concentration of the polypeptide based on a signal which is obtained from the polypeptide itself and the intensity of which directly correlates with the number of molecules of the polypeptide present in the sample. Such a signal—sometimes referred to herein as intensity signal may be obtained, e.g., by measuring an intensity value of a specific physical or chemical property of the polypeptide. Indirect measuring includes measuring of a signal obtained from a secondary component (i.e. a component not being the polypeptide itself) or a biological read out system, e.g., measurable cellular responses, ligands, labels, or enzymatic reaction products.
In accordance with the present invention, determining the amount of a polypeptide biomarker can be achieved by all known means for determining the amount of a polypeptide in a sample.
Said means comprise immunoassay devices and methods which may utilize labeled molecules in various sandwich, competition, or other assay formats. Preferably, the immunoassay device is an antibody microarray. Said assays will develop a signal which is indicative for the presence or absence of the polypeptide and, thus, the biomarker.
Moreover, the signal strength can, preferably, be correlated directly or indirectly (e.g. reverse-proportional) to the amount of polypeptide present in a sample. Further suitable methods comprise measuring a physical or chemical property specific for the polypeptide such as its precise molecular mass or NMR spectrum. Said methods comprise, preferably, biosensors, optical devices coupled to immunoassays, biochips, analytical devices such as mass-spectrometers, NMR-analyzers, or chromatography devices. Further, methods include micro-plate ELISA-based methods, fully-automated or robotic immunoassays, CBA (an enzymatic Cobalt Binding Assay), and latex agglutination assays.
Preferably, determining the amount of a polypeptide biomarker comprises the steps of (a) contacting a cell capable of eliciting a cellular response the intensity of which is indicative of the amount of the polypeptide with the said polypeptide for an adequate period of time, (b) measuring the cellular response. For measuring cellular responses, the sample or processed sample is, preferably, added to a cell culture and an internal or external cellular response is measured. The cellular response may include the measurable expression of a reporter gene or the secretion of a substance, e.g. a peptide, polypeptide, or a small molecule. The expression or substance shall generate an intensity signal which correlates to the amount of the polypeptide.
Also preferably, determining the amount of a polypeptide biomarker comprises the step of measuring a specific intensity signal obtainable from the polypeptide in the sample. As described above, such a signal may be the signal intensity observed at a mass to charge (m/z) variable specific for the polypeptide observed in mass spectra or a NMR spectrum specific for the polypeptide.
Determining the amount of a polypeptide biomarker may, preferably, comprise the steps of (a) contacting the polypeptide with a specific ligand, (b) removing non-bound ligand, (c) measuring the amount of bound ligand. The bound ligand will generate an intensity signal. Binding according to the present invention includes both covalent and non-covalent binding. A ligand according to the present invention can be any compound, e.g., a peptide, polypeptide, nucleic acid, or small molecule, binding to the polypeptide described herein. Preferred ligands include antibodies, nucleic acids, peptides or polypeptides such as receptors or binding partners for the polypeptide and fragments thereof comprising the binding domains for the peptides, and aptamers, e.g. nucleic acid or peptide aptamers. Methods to prepare such ligands are well-known in the art. For example, identification and production of suitable antibodies or aptamers is also offered by commercial suppliers. The person skilled in the art is familiar with methods to develop derivatives of such ligands with higher affinity or specificity. For example, random mutations can be introduced into the nucleic acids, peptides or polypeptides. These derivatives can then be tested for binding according to screening procedures known in the art, e.g. phage display. Antibodies as referred to herein include both polyclonal and monoclonal antibodies, as well as fragments thereof, such as Fv, Fab, scFv and F(ab)2 fragments that are capable of binding antigen or hapten. The present invention also includes single chain antibodies and humanized hybrid antibodies wherein amino acid sequences of a non-human donor antibody exhibiting a desired antigen-specificity are combined with sequences of a human acceptor antibody. Alternatively, chimeric mouse antibodies with rabbit Fc can be used. The donor sequences will usually include at least the antigen-binding amino acid residues of the donor but may comprise other structurally and/or functionally relevant amino acid residues of the donor antibody as well. Such hybrids can be prepared by several methods well known in the art. Preferably, the ligand or agent binds specifically to the polypeptide. Specific binding according to the present invention means that the ligand or agent should not bind substantially to (“cross-react” with) another peptide, polypeptide or substance present in the sample to be analyzed. Preferably, the specifically bound polypeptide should be bound with at least 3 times higher, more preferably at least 10 times higher and even more preferably at least 50 times higher affinity than any other relevant peptide or polypeptide. Non-specific binding may be tolerable, if it can still be distinguished and measured unequivocally, e.g. according, to its size on a Western Blot, or by its relatively higher abundance in the sample. Binding, of the ligand can be measured by any method known in the art. Preferably, said method is semiquantitative or quantitative. Suitable methods are described in the following. First, binding of a ligand may be measured directly, e.g. by mass spectroscopy, NMR or surface plasmon resonance. Second, if the ligand also serves as a substrate of an enzymatic activity of the polypeptide of interest, an enzymatic reaction product may be measured (e.g. the amount of a protease can be measured by measuring the amount of cleaved substrate, e.g. on a Western Blot). Alternatively, the ligand may exhibit enzymatic properties itself and the “ligand/polypeptide” complex or the ligand which was bound by the polypeptide, respectively, may be contacted with a suitable substrate allowing detection by the generation of an intensity signal. For measurement of enzymatic reaction products, preferably the amount of substrate is saturating. The substrate may also be labeled with a detectable label prior to the reaction. Preferably, the sample is contacted with the substrate for an adequate period of time. An adequate period of time refers to the time necessary for a detectable, preferably measurable, amount of product to be produced. Instead of measuring the amount of product, the time necessary for appearance of a given (e.g. detectable) amount of product can be measured. Third, the ligand may be coupled covalently or non-covalently to a label allowing detection and measurement of the ligand. Labeling may be done by direct or indirect methods. Direct labeling involves coupling of the label directly (covalently or non-covalently) to the ligand. Indirect labeling involves binding (covalently or non-covalently) of a secondary ligand to the first ligand. The secondary ligand should specifically bind to the first ligand. Said secondary ligand may be coupled with a suitable label and/or be the target (receptor) of tertiary ligand binding to the secondary ligand. The use of secondary, tertiary or even higher order ligands is often used to increase the signal. Suitable secondary and higher order ligands may include antibodies, secondary antibodies, and the well-known streptavidin-biotin system (Vector Laboratories, Inc.). The ligand or substrate may also be “tagged” with one or more tags as known in the art. Such tags may then be targets for higher order ligands. Suitable tags include biotin, digoxygenin, His-Tag, Glutathion-S-Transferase, FLAG, GFP, myc-tag, influenza A virus haemagglutinin (HA), maltose binding protein, and the like. In the case of a peptide or polypeptide, the tag is preferably at the N-terminus and/or C-terminus. Suitable labels are any labels detectable by an appropriate detection method. Typical labels include gold particles, latex beads, acridan ester, luminol, ruthenium, enzymatically active labels, radioactive labels, magnetic labels (“e.g. magnetic beads”, including paramagnetic and superparamagnetic labels), and fluorescent labels. Enzymatically active labels include e.g. horseradish peroxidase, alkaline phosphatase, beta-Galactosidase, Luciferase, and derivatives thereof. Suitable substrates for detection include di-amino-benzidine (DAB), 3,3′-5,5′-tetramethylbenzidine, NBT-BCIP (4-nitro blue tetrazolium chloride and 5-bromo-4-chloro-3-indolyl-phosphate, available as ready-made stock solution from Roche Diagnostics), CDP-Star™ (Amersham Biosciences), ECF™ (Amersham Biosciences). A suitable enzyme-substrate combination may result in a colored reaction product, fluorescence or chemo luminescence, which can be measured according to methods known in the art (e.g. using a light-sensitive film or a suitable camera system). As for measuring the enyzmatic reaction, the criteria given above apply analogously. Typical fluorescent labels include fluorescent proteins (such as GFP and its derivatives), Cy3, Cy5, or Dy-547, Dy-549, Dy-647, Dy-649 (Dyomics, Jena, Germany) or Texas Red, Fluorescein, and the Alexa dyes (e.g. Alexa 568). Further fluorescent labels are available e.g. from Molecular Probes (Oregon). Also the use of quantum dots as fluorescent labels is contemplated. Typical radioactive labels include <35>S, <125>I, <32>P, <33>P and the like. A radioactive label can be detected by any method known and appropriate, e.g. a light-sensitive film or a phosphor imager. Suitable measurement methods according the present invention also include precipitation (particularly immunoprecipitation), electrochemiluminescence (electro-generated chemiluminescence), RIA (radioimmunoassay), ELISA (enzyme-linked immunosorbent assay), sandwich enzyme immune tests, electrochemiluminescence sandwich immunoassays (ECLIA), dissociation-enhanced lanthanide fluoro immuno assay (DELFIA), scintillation proximity assay (SPA), FRET based proximity assays (Anal Chem. 2005 Apr. 15;77(8):2637-42.) or Ligation proximity assays (Nature Biotechnology 20, 473-477 (2002), turbidimetry, nephelometry, latex-enhanced turbidimetry or nephelometry, or solid phase immune tests. Further methods known in the art (such as gel electrophoresis, 2D gel electrophoresis, SDS polyacrylamid gel electrophoresis (SDS-PAGE), Western Blotting, and mass spectrometry), can be used alone or in combination with labeling or other detection methods as described above.
The amount of a polypeptide biomarker may be, also preferably, determined as follows: (a) contacting a solid support comprising a ligand for the polypeptide as specified above with a sample comprising the polypeptide and (b) measuring the amount of polypeptide which is bound to the support. The ligand, preferably, chosen from the group consisting of nucleic acids, peptides, polypeptides, antibodies and aptamers, is preferably present on a solid support in immobilized form. Materials for manufacturing solid supports are well known in the art and include, inter alia, commercially available column materials, polystyrene beads, latex beads, magnetic beads, colloid metal particles, glass and/or silicon chips and surfaces, nitrocellulose strips, membranes, sheets, duracytes, wells and walls of reaction trays, plastic tubes etc. The ligand or agent may be bound to many different carriers. Examples of well-known carriers include glass, polystyrene, polyvinyl chloride, polypropylene, polyethylene, polycarbonate, dextran, nylon, amylases, natural and modified celluloses, polyacrylamides, agaroses, and magnetite. The nature of the carrier can be either soluble or insoluble for the purposes of the invention. Suitable methods for fixing/immobilizing said ligand are well known and include, but are not limited to ionic, hydrophobic, covalent interactions and the like. It is also contemplated to use “suspension arrays” as arrays according to the present invention (Nolan 2002, Trends Biotechnol. 20(I):9-12). In such suspension arrays, the carrier, e.g. a microbead or microsphere, is present in suspension. The array consists of different microbeads or microspheres, possibly labeled, carrying different ligands. Methods of producing such arrays, for example based on solid-phase chemistry and photo-labile protective groups, are generally known, see e.g., U.S. Pat. No. 5,744,305.
The term “amount” as used herein encompasses the absolute amount of a biomarker, the relative amount or concentration of the said biomarker as well as any value or parameter which correlates thereto or can be derived therefrom. Such values or parameters comprise intensity signal values from all specific physical or chemical properties obtained from the said biomarker by direct measurements, e.g., intensity values in mass spectra or NMR spectra or surface Plasmon resonance spectra. Moreover, encompassed are all values or parameters which are obtained by indirect measurements specified elsewhere in this description, e.g., response levels determined from biological read out systems in response to the peptides or intensity signals obtained from specifically bound ligands. It is to be understood that values correlating to the aforementioned amounts or parameters can also be obtained by all standard mathematical operations. The term “comparing” as used herein encompasses comparing the amount of the biomarker comprised by the sample to be analyzed with an amount of a suitable reference source specified elsewhere in this description it is to be understood that comparing as used herein refers to a comparison of corresponding parameters or values, e.g., an absolute amount is compared to an absolute reference amount while a concentration is compared to a reference concentration or an intensity signal obtained from a test sample is compared to the same type of intensity signal of a reference sample. The comparison referred to in step (b) of the method of the present invention may be carried out manually or computer assisted. For a computer assisted comparison, the value of the determined amount may be compared to values corresponding to suitable references which are stored in a database by a computer program. The computer program may further evaluate the result of the comparison, i.e. automatically provide the desired assessment in a suitable output format. Based on the comparison of the amount determined in step a) and the reference amount, it is possible to diagnose pancreatic cancer.
Accordingly, the term “reference” as used herein refers to amounts of the biomarker which allow for determining whether a subject suffers from pancreatic cancer, or not. Therefore, the reference may either be derived from (i) a subject known to suffer from pancreatic cancer or (ii) a subject known not to suffer from pancreatic cancer, i.e. a healthy subject with respect to pancreatic cancer and, preferably, other diseases as well. Preferably, said reference is derived from a sample of a subject known not to suffer from cancer. More preferably, an increase in the amount of the said at least one biomarker selected from the biomarkers shown in Tables 2a or 3a compared to the reference is indicative for pancreas cancer whereas a decrease in the amount of the said at least one biomarker selected from the biomarkers shown in Tables 2b or 3b compared to the reference is indicative for pancreas cancer.
Moreover, the references, preferably, define threshold amounts or thresholds. Suitable reference amounts or threshold amounts may be determined by the method of the present invention from a reference sample to be analyzed together, i.e. simultaneously or subsequently, with the test sample. A preferred reference amount serving as a threshold may be derived from the upper limit of normal (ULN), i.e. the upper limit of the physiological amount to be found in a population of subjects (e.g. patients enrolled for a clinical trial). The ULN for a given population of subjects can be determined by various well known techniques. A suitable technique may be to determine the median of the population for the peptide or polypeptide amounts to be determined in the method of the present invention. Suitable threshold amounts can also be identified by ROC plots depicting the overlap between the two distributions by plotting the sensitivity versus 1—specificity for the complete range of decision thresholds. On the y-axis is sensitivity, or the true-positive fraction, defined as (number of true-positive test results)/(number of true-positive number of false-negative test results). This has also been referred to as positivity in the presence of a given disease. It is calculated solely from the affected subgroup. On the x-axis is the false-positive fraction, or 1—specificity, defined as (number of false-positive results)/(number of true-negative+number of false-positive results). It is an index of specificity and is calculated entirely from the unaffected subgroup. Because the true- and fake-positive fractions are calculated entirely separately, by using the test results from two different subgroups, the ROC plot is independent of the prevalence of disease in the sample. Each point on the ROC plot represents a sensitivity/1—pair corresponding to a particular decision threshold. A test with perfect discrimination (no overlap in the two distributions of results) has an ROC plot that passes through the upper left corner, where the true-positive fraction is 1.0, or 100% (perfect sensitivity), and the fake-positive fraction is 0 (perfect specificity). The theoretical plot for a test with no discrimination (identical distributions of results for the two groups) is a 45 degrees diagonal line from the lower left corner to the upper right corner. Most plots fall in between these two extremes.
Advantageously, it has been found in the study underlying the present invention that the biomarkers listed in the tables are indicative for the presence or absence of a pancreatic cancer in a subject. Thereby, pancreatic cancer can be determined at early stages where the pancreatic cancer elicits rather unspecific clinical symptoms. As a consequence of the early diagnosis by the method of the present invention, therapeutic approaches can be applied earlier and may, therefore, allow for a more successful treatment of the disease by identifying subjects in need of a therapy at an early stage. Moreover, the findings underlying the aforementioned method also allow for an improved clinical management of pancreatic cancer since patients can be identified which need intensive monitoring. Further, the success of a therapy can be monitored. In the studies underlying this invention, urine samples from healthy patients and patients suffering from pancreatic cancer were analyzed using antibody microarrays comprising antibodies against 810 different polypeptides. Differences in the polypeptide amounts between healthy and diseased patients which turned out to be statistically significant are shown in the Tables below and could be used as biomarkers for diagnosing pancreatic cancer.
The present invention also relates to a method for identifying whether a subject is in need of a pancreas cancer therapy comprising the steps of the aforementioned methods and the further step of identifying a subject in need of a pancreas cancer therapy if said subject is to be diagnosed to suffer from pancreas cancer.
Preferably, the term “pancreas cancer therapy” comprises surgery, radiotherapy or drug treatment. Preferred therapies include resect neoplasm (for patients with sporadic disease, pancreaticoduodenectomy, tail pancreatectomy), pancreatectomy, adjuvant 5-FU based chemotherapy, adjuvant gemcitabine chemotherapy, doxorubicin (DOX), folinic acid (FA), or Mytomycin (MMC) adjuvant based chemotherapies, administration of one or more of the following drugs: 5-Fluorouracil (5FU, an inhibitor of thymidylate synthetase), Gemcitabine (nucleoside analogue), Capecitabine (Xeloda, a new oral, fluoropyrimidine carbamate that is sequentially converted to 5FU by three enzymes located in the liver and in tumours, including pancreatic cancer), Gemcitabine combined with Capecitabine, platinum-based agents, erlotinib (EGFR tyrosine kinase inhibitor, Trial: PA3 (Canada, USA)), cetuximab (monoclonal antibody to EGFR, Trial: SWOG S0205 (USA), bevacizumab (anti-VEGFR antibody (Avastin), Trial: CALGB 80303 (USA), Avita (Europe, Closed prematurely)), or GV1001 [+GMCSF] (peptide vaccine targeting telomerase (GV11001 (Europe, Australia) TeloVac (UK)). Radiotherapy has been widely used for the treatment of pancreatic cancer. The main drawback is the limit on the dosage owing to the close proximity of adjacent radiosensitive organs. External beam radiotherapy is routinely used with 5FU as a radiosensitising agent chemoradiotherapy), although gemcitabine is now being evaluated as an alternative radio-sensitiser. Newer techniques such as conformal radiotherapy are now being used, but these studies almost invariably employ follow-on chemotherapy once the chemoradiotherapy has been completed. A recent meta-analysis demonstrated that chemoradiotherapy is better than radiotherapy alone and that there is no survival difference between chemoradiotherapy plus follow-on chemotherapy and chemotherapy alone. A recent phase III study compared chemoradiotherapy and follow-on gemcitabine with gemcitabine alone in patients with locally advanced disease. The trial was closed prematurely because of significant toxicity in the combination arm and significantly reduced median survival in the combination arm (8.4 vs 14.3 months; p=0.014).
The phrase “a subject in need of a pancreas cancer therapy” as used herein relates to a subject which suffers from pancreatic cancer as diagnosed by the method of the present invention. It will be understood that a pancreas therapy is at least beneficial for such subjects being confirmed by the diagnostic method of the present invention. As discussed above, the diagnostic method of the present invention already allows identifying subjects at the early onset of the disease. Accordingly, such subjects which may not be unambiguously identifiable based on their clinical symptoms.
The present invention relates to a device for diagnosing pancreas cancer in a sample of a subject comprising:
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- (a) an analyzing unit for the said sample of the subject comprising a detection agent for at least one biomarker as shown in any one of Tables 1, 2a, 2b, 3a or 3b, said detection agent allowing for the determination of the amount of the said at least one biomarker in the sample; and operatively linked thereto,
- (b) an evaluation unit comprising a data processing unit and a data base, said data base comprising a stored reference and said data processing unit being capable of carrying out a comparison of the amount of the at least one biomarker determined by the analyzing unit and the stored reference thereby establishing the diagnosis.
The term “device” as used herein relates to a system of means comprising at least the aforementioned analyzing unit and the evaluation unit operatively linked to each other as to allow the diagnosis. Preferred detection agents to be used for the device of the present invention are disclosed above in connection with the method of the invention. Preferably, detection agents are antibodies or aptameres. How to link the units of the device in an operating manner will depend on the type of units included into the device. For example, where units for automatically determining the amount of the biomarker are applied, the data obtained by said automatically operating unit can be processed by, e.g., a computer program in order to obtain the desired results. Preferably, the units are comprised by a single device in such a case. The computer unit, preferably, comprises a database including the stored reference(s) as well as a computer-implemented algorithm for carrying out a comparison of the determined amounts for the polypeptide biomarkers with the stored reference of the database. Computer-implemented as used herein refers to a computer-readable program code tangibly included into the computer unit. The results may be given as output of raw data which need interpretation by the clinician. Preferably, the output of the device is, however, processed, i.e. evaluated, raw data the interpretation of which does not require a clinician.
In a preferred device of the invention, the detection agent, preferably, an antibody, is immobilized on a solid support in an array format. It will be understood that a device according to the present invention can determine the amount of more than one biomarker simultaneously. To this end, the detection agents may be immobilized on a solid support and arranged in an array format, e.g., in a so called “microarray”.
The present invention also relates to a kit comprising a detection agent for determining the amount of at least one biomarker as shown in any one of Tables 1, 2a, 2b, 3a or 3b and an evaluation instructions for establishing the diagnosis.
The term “kit” as used herein refers to a collection of the aforementioned agent and the instructions provided in a ready-to-use manner for determining the biomarker amount in a sample. The agent and the instructions are, preferably, provided in a single container. Preferably, the kit also comprises further components which are necessary for carrying out the determination of the amount of the biomarker. Such components may be auxiliary agents which are required for the detection of the biomarker or calibration standards. Moreover, the kit may, preferably, comprise agents for the detection of more than one biomarker.
In principle, the present invention contemplates the use of at least one biomarker as shown in any one of Tables 1, 2a, 2b, 3a or 3b, a detection agent therefore, the aforementioned devices or the aforementioned kits for diagnosing in a sample of a subject pancreas cancer.
All references cited in this specification are herewith incorporated by reference with respect to their entire disclosure content and the disclosure content specifically mentioned in this specification.
The following Examples shall merely illustrate the invention. They shall not be construed, whatsoever, to limit the scope of the invention.
Example: Identification of Polypeptide Biomarkers for Pancreas CancerIn order to identify polypeptides with differential abundance in patients suffering from pancreatic cancer a study was performed utilising antibody microarrays. In antibody microarrays antibodies are immobilised at distinct locations on a solid support. After array printing with microarraying robots, the microarrays are blocked in order to minimize unspecific protein adsorption on the array surface. The arrays are then incubated with the protein samples of interest. In this study the protein fraction of the samples was directly labeled by a fluorescent dye, using NHS-ester chemistry.
For inclusion on the array specific target proteins were selected by transcriptional studies on pancreatic cancer and other cancer entities. The antibody microarray applied in this study comprised 810 antibodies that were directed at 741 different proteins. All antibodies were immobilised in duplicates. The study involved twelve urine samples from six patients with pancreatic adenocarcinoma and six healthy individuals, both groups equally divided into male and female.
For the analyses from the 12 individuals midstream urine samples were collected and pH was adjusted to 7. The samples were desalted and concentrated as described in detail elsewhere (Weeks et al. (2008) Proteomics: Clin. Appl. 2,1047-57). Briefly, samples were desalted using Zeba spin columns (Thermo Scientific). The flow-through was frozen in liquid nitrogen and lyophilised to dryness using an ILMVAC Freeze Dryer. Lyophilised samples were resolubilised in distilled water and concentrated with Vivaspin 15 R-5 kDa (Sartorius Vivascience, Hannover, Germany).
The protein samples were labeled with Dy-549 (Dyomics, Jena, Germany). Additionally, a common reference was prepared by pooling of samples and subsequent labeling with Dy-649 (Dyomics, Jena, Germany). All protein samples were labeled at a protein concentration of 4 mem with 0.4 mg/mL of the NHS-esters of the fluorescent dyes in 100 mM sodium bicarbonate buffer (pH 9.0), 1% (w/v) Triton-100 on a shaker at 4° C. After 1 h, the reactions were stopped by addition of hydroxylamine to 1 M. Unreacted dye was removed 30 min later and the buffer changed to PBS using Zeba Desalt columns (Thermo Scientific). Subsequently, Complete Protease Inhibitor Cocktail tablets (Roche, Mannheim, Germany) were added as recommended by the manufacturer.
Incubations were performed in homemade incubation chambers, which were attached to the array slides with Terostat-81 (Henkel, Düsseldorf, Germany). The inner dimensions of the incubation chambers matched the area of the array (9 mm×18 mm) with an additional border of 2 mm and a height of 5 mm. Prior to adding the labeled protein samples, the arrays were blocked in a casein-based blocking solution (Candor Biosciences, Weißensberg, Germany) on a Slidebooster instrument (Advalytix, Munich, Germany) for 3 h. Incubation was performed with labeled samples diluted 1:20 in blocking solution, containing 1% (w/v) Tween-20 and Complete Protease Inhibitor Cocktail for 15 h in a total volume of 600 μl. All samples were incubated in a dual-colour assay. In this assay each sample is incubated in combination with the common reference labeled with with a different dye. After incubation, slides were thoroughly washed with PBSTT prior and after detaching the incubation chambers. Finally, the slides were rinsed with 0.1×PBS and distilled water and dried in a stream of air.
Slide scanning was done on a ScanArray 5000 or 4000 XL unit (Packard, Billerica, USA) using the identical instrument laser power and PMT in each experiment. Spot segmentation was performed with GenePix Pro 6.0 (Molecular Devices, Union City, USA). Resulting data were analyzed using the LIMMA package of R-Bioconductor after uploading the mean signal and median background intensities. The intensity values were background-corrected using the Normexp method with an offset of 50. The log-ratios of the two colour channels were normalized with global Lowess. For differential analyses of the depletion experiment a two-factorial linear model (gender and cancer) was fitted using LIMMA resulting in a F-test based on moderated statistics. All p-values were adjusted for multiple testing by controlling the false discovery rate according to Benjamini and Hochberg.
Using LIMMA analysis, 11 proteins were found at differential levels between healthy males and females at a significance level of adj. P<0.05 with the most prominent one being KLK3 (also known as PSA; p=1.10-5). Proteins with different abundances in patients and controls differed highly in female and male. Therefore, separated gender specific comparisons were performed. We found two proteins that differ between healthy and diseased females, whereas 17 proteins showed significantly differential levels within the male subgroup. The respective log-fold changes between cancerous samples and healthy controls are summarized in the tables below.
For validation, a classification test (prediction analyses for microarrays/PAM) was performed using the pamr-package for the statistical system R. For this the samples were grouped according to health status and gender. In an inner loop a classificator was optimised by leave-one-out procedure. In an outer loop the accuracy of the respective classificator was estimated by a leave-one-out cross validation. Even within this small sample set an overall accuracy of 72% was obtained. Pancreatic cancer could be detected with a sensitivity and a specificity of 83%.
The results of the aforementioned study are summarized in the following Tables:
Claims
1-16. (canceled)
17. A method for diagnosing pancreas cancer in a subject comprising the steps of:
- (a) determining in a sample of a subject suspected to suffer from pancreas cancer the amount of at least one biomarker selected from the biomarkers shown in Table 1; and
- (b) comparing the amount of the at least one biomarker with a reference, whereby pancreas cancer is to be diagnosed.
18. The method of claim 17, wherein the at least one biomarker is selected from the biomarkers shown in Tables 2a or 2b and wherein the subject is a female.
19. The method of claim 17, wherein the at least one biomarker is selected from the biomarkers shown in Tables 3a or 3b and wherein the subject is a male.
20. The method of claim 17, wherein the reference is derived from a sample of a subject known not to suffer from cancer.
21. The method of claim 20, wherein an increase in the amount of the at least one biomarker selected from the biomarkers shown in Tables 2a or 3a compared to the reference is indicative for pancreas cancer.
22. The method of claim 20, wherein a decrease in the amount of the at least one biomarker selected from the biomarkers shown in Tables 2b or 3b compared to the reference is indicative for pancreas cancer.
23. A method for identifying whether a subject is in need of a pancreas cancer therapy comprising the steps of the method of claim 17, and a further step of identifying a subject in need of a pancreas cancer therapy if the subject is to be diagnosed to suffer from pancreas cancer.
24. The method of claim 23, wherein the pancreas cancer therapy comprises surgery, radiotherapy or drug treatment.
25. The method of claim 17, wherein the sample is a urine sample.
26. The method of claim 17, wherein the subject is a human.
27. The method of claim 17, wherein the pancreas cancer is pancreas adenocarcinoma.
28. A device for diagnosing pancreas cancer in a sample of a subject comprising:
- (a) an analyzing unit for the sample of the subject comprising a detection agent for at least one biomarker as shown in any one of Tables 1, 2a, 2b, 3a or 3b, the detection agent allowing for the determination of the amount of the at least one biomarker in the sample; and operatively linked thereto,
- (b) an evaluation unit comprising a data processing unit and a data base, the data base comprising a stored reference and the data processing unit being capable of carrying out a comparison of the amount of the at least one biomarker determined by the analyzing unit and the stored reference, thereby establishing the diagnosis.
29. The device of claim 28, wherein the detection agent is an antibody.
30. The device of claim 29, wherein the antibody is immobilized on a solid support in an array format.
31. A kit comprising a detection agent for determining the amount of at least one biomarker as shown in any one of Tables 1, 2a, 2b, 3a or 3b and evaluation instructions for establishing the diagnosis.
Type: Application
Filed: Jun 26, 2023
Publication Date: Feb 1, 2024
Applicants: Deutsches Krebsforschungszentrum (Heidelberg), Queen Mary University of London (London)
Inventors: Christoph SCHRÖDER (Heidelberg), Jörg HOHEISEL (Wiesloch), Tatjana CRNOGORAC-JURCEVIC (Chislehurst)
Application Number: 18/214,434
