Anti-VEGF Therapy in Cancer: A Double-Edged Sword

Vascular endothelial growth factor (VEGF) is a mitogen that plays a crucial role in angiogenesis and lymphangiogenesis. It is involved in tumor survival through inducing tumor angiogenesis and by increasing chemoresistance through autocrine signaling. Because of its importance in tumor formation and survival, several medications have been developed to inhibit VEGF and reduce blood vessel formation in cancer. Although these medications have proven to be effective for late-stage and metastatic cancers, they have been shown to cause side effects such as hypertension, artery clots, complications in wound healing, and, more rarely, gastrointestinal perforation and fistulas. Current research in using anti-VEGF medication as a part of cancer treatments is focusing on elucidating the mechanisms of tumor resistance to VEGF medication, developing predictive biomarkers that assess whether a patient will respond to VEGF therapy and creating novel treatments and techniques that increase the efficacy of antiangiogenic medication. This chapter aims to review the role of VEGF in tumor angiogenesis and metastasis, the structure and function of VEGF and its receptors, and VEGF's role in cancer are discussed. Furthermore, tumor therapies targeting VEGF along with their side effects are presented and, finally, new directions in anti-VEGF therapy are considered along with the challenges.