Many such biomarkers, for example, BRAF V600E (Melanoma/Colorectal Cancer); EGFR (Nonsmall cell lung carcinoma); and HER-2 (Breast Cancer), are associated with monitoring activation state and mutation status of known drug targets to predict response to therapy.5–7 Thus, the personalized medicine approach is well suited to target-directed drug discovery strategies where target pathways are clearly defined. This evidence concerns the gene ERBB2 and breast cancer.