| 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. |