Abstract: Methods for treating breast cancer, specifically cancers resistant to treatment With one or more known breast cancer treatment drugs, and related patient selection strategies for predicting patient response to drug therapy, such strategies including detecting tile presence or absence in a patient of one or more of PIK3CA gene amplification a mutation in PIK3CA, and a decrease in PTEN protein expression, and treating a patient positive for the presence of one or more of same by administering to the subject a pan-ErbB tifrosine kinase inhibitor.

Abstract: Methods for treating breast cancer, specifically cancers resistant to treatment with one or more known breast cancer treatment drugs, and related patient selection strategies for predicting patient response to drug therapy, such strategies including detecting the presence or absence in a patient of one or more of PIK3CA gene amplification, a mutation in PIK3CA, and a decrease in PTEN protein expression, and treating a patient positive for the presence of one or more of same by administering to the subject a pan-ErbB tyrosine kinase inhibitor.

Abstract: Methods for treating breast cancer, specifically cancers resistant to treatment With one or more known breast cancer treatment drugs, and related patient selection strategies for predicting patient response to drug therapy, such strategies including detecting the presence or absence n a patient o one or inure of PIK3CA gene amplification, a mutation in PIK3CA, and a decrease in PTEN protein expression, and treating a patient positive for the presence of one or more of same by administering to the subject a pan-ErbB tyrosine kinase inhibitor.

Abstract: Methods for treating breast cancer, specifically cancers resistant to treatment with one or more known breast cancer treatment drugs, and related patient selection strategies for predicting patient response to drug therapy, such strategies including detecting the presence or absence in a patient of one or more of PIK3CA gene amplification, a mutation in PIK3CA, and a decrease in PTEN protein expression, and treating a patient positive for the presence of one or more of same by administering to the subject a pan-ErbB tyrosine kinase inhibitor.

Abstract: A cut-point in the quantitative measurement of PTEN protein expression that accurately identifies tumors with two inactivated alleles of the PTEN gene. Patients with a normalized PTEN score of PTEN null will be treated with a pan-ErbB tyrosine kinase inhibitor. A normalized PTEN protein expression score is obtained by comparing the tumor PTEN OD expression value with the non-malignant PTEN OD expression value.