In the history of personalized medicine, Roche/Genentech was the first company to successfully use the “therapy-test” co-development model, bringing Herceptin® (trastuzumab, Genentech-Roche, San Francisco, USA) to the market in 1998 along with Dako’s immunohistochemistry assay HercepTestTM (Dako, Agilent Technologies, Santa Clara, USA), targeting HER2 overexpression in advanced breast cancer. This evidence concerns the gene ERBB2 and breast cancer.