KDR and metastatic colorectal cancer: Bevacizumab, the first and most commonly used anti-angiogenic drug, prevents the activation of VEGFR signaling by specifically targeting VEGFA to Ferrara et al. (16), Kerr (35), and Ramezani et al. (36) Although bevacizumab is a molecular-targeted therapy and served as the first-line treatment option for metastatic colorectal cancer, breast cancer, renal cell carcinoma, and advanced non-small cell lung cancer (32), its resistance limits its therapeutic efficacy in the clinical treatment.