Patent ID: 7825094

Claim:
A method of treating a patient having breast cancer characterized by breast cancer cells that have elevated levels of HER-2 expression as compared to non-cancerous cells of the same type, comprising: providing breast cancer cells from said patient; testing said provided cells for one or more of the gene copy number of HER-2 the amount of HER-2 mRNA, or the amount of HER-2 protein as an indication of the level of HER-2 expression; and if said level of HER-2 expression is elevated as compared to non-cancerous cells of the same type, administering to said patient a pharmaceutically effective amount of an HSP90 inhibitor, wherein said HSP90 inhibitor has an IC 50 at least two-fold lower for said provided cells in said patient having elevated Her-2 than for cells that do not have elevated Her-2 and the administered amount is correspondingly lower than the amount that would be required for cells that do not have elevated Her-2, and wherein said method of treating a patient further comprises testing to monitor therapeutic effect after said administration by measuring a molecular marker indicative of the level of HER-2 wherein said inhibitor consists essentially of an ansamycin that binds into the ATP-binding site of a HSP90.