VEGF expression in pancreatic cancer and other malignancies: a review of the literature

Angiogenesis is a crucial event for tumor growth and it is regulated predominantly by several different growth factors. Vascular endothelial growth factor protein family (VEGF) and its receptors are probably the most important tissue factors responsible for angioblast differentiation and tube formation. VEGF protein family currently comprises several members: VEGF (or VEGF-A), VEGF-B, VEGF-C and VEGF-D, VEGF-F, placental growth factor (PlGF), and their receptors VEGFR-1, VEGFR-2 and VEGFR-3. VEGF is a key angiogenic growth factor and its level of expression is a critical marker for detection of the angiogenic diseases. The potent role of VEGF in tumor angiogenesis has been widely described in the past decade, being expressed in most types of nondigestive and digestive cancers. VEGF family members play an important role in the development of pancreatic cancer (especially VEGF-A, VEGF-C, VEGF-D, VEGFR-1 and VEGFR-2). VEGF-A is the most specific and prominent angiogenic factor among all family members and VEGFR-2 is the most important receptor in evaluating the angiogenesis in pancreatic cancer. Thus, VEGF overexpression may be considered as a diagnostic marker and as a poor prognostic factor of the disease.