Abstract: Methods are provided for identifying whether a tumor will be responsive to treatment with an anti-EGFR agent. Specific protein fragment peptides are precisely detected and quantitated by SRM-mass spectrometry directly in tumor cells collected from tumor tissue that was obtained from a cancer patient and compared to reference levels in order to determine if the lung cancer patient will positively respond to treatment with an anti-EGFR agent such as, for example, pamitumumab and/or erbitux.

Abstract: Methods are provided for treating a gastric cancer patient. A specific Met fragment peptide is precisely quantitated by SRM-mass spectrometry directly in gastric tumor cells collected from gastric tumor tissue that was obtained from the cancer patient and compared to a reference level. If the Met peptide is below the reference level a second therapeutic regimen is used to treat the patient whereas if the Met peptide is above the reference level then a first therapeutic regimen combining, for example, the second regimen with one or more Met inhibitor therapeutic agents may be used to treat the patient.

Abstract: Methods are provided for treating a gastric cancer patient. A specific Met fragment peptide is precisely quantitated by SRM-mass spectrometry directly in gastric tumor cells collected from gastric tumor tissue that was obtained from the cancer patient and compared to a reference level. If the Met peptide is below the reference level a second therapeutic regimen is used to treat the patient whereas if the Met peptide is above the reference level then a first therapeutic regimen combining, for example, the second regimen with one or more Met inhibitor therapeutic agents may be used to treat the patient.