Molecular diagnosis of solid tumors

This review highlights three examples of novel targeted therapeutics for solid tumors that are currently approved in Japan: 1) Trastuzumab (Herceptin) for patients with metastatic breast cancer that demonstrates overexpression of HER2/neu; 2) Imatinib mesylate (Glivec) for patients with gastrointestinal tumors, of which tumor cells express c-Kit; and 3) Gefitini (Iressa) for patients with advanced non-small cell lung cancers, which response to gefitinib is recently suggested to be associated with EGFR mutation. In these molecular targeted therapies, diagnostic tools to verify the presence of an appropriate molecular target is crucial to the success, and thus the methods and its interpretation are discussed in this review.