Several small molecule VEGF/VEGFR pathway inhibitors have been approved for the treatment of metastatic colorectal cancer, gastrointestinal stromal tumors, hepatocellular carcinoma, non-small-cell lung cancer, renal cell carcinoma, soft tissue sarcoma, and medullary thyroid cancer, and are under the development of a number of other oncology indications, including pancreatic cancer, ovarian cancer, breast cancer, prostate, head and neck cancers [17]. This evidence concerns the gene KDR and gastrointestinal stromal tumor.