Author(s): Dr. Salman T
Colorectal cancer is the second most common type of cancer in women and the third one in men. In terms of worldwide prevalence, it ranks third [1]. The prognosis of colorectal cancer is dependent on the stages in the TNM system. The development of tumors and metastases depend on a delicate balance between endogenous angiogenic factors, which cause the formation of new blood vessels, and anti-angiogenic factors [2]. The process of angiogenesis consists of a multitude of sequential and interconnected steps including positive and negative regulators [3]. Today, it is known that angiogenesis is not only essential for tumor growth but also is responsible for the cancerous transformation of a premalignant tumor, circulation of cancer cells, and the transformation of micro-metastases into typical metastatic lesions [4]. Without doubt, the vascular endothelial growth factor (VEGF) is the most important molecule that plays a role in the angiogenetic process [5,6]. VEGF does not only induce the proliferation of endothelial cells but also increases the vascular permeability and causes the formation of a fibrin matrix that enables stromal cell invasion by increasing the extravasation of proteins through tumor vessels [7]. The data provided by preclinical and clinical studies indicate that VEGF is the predominant angiogenic factor in colorectal cancer [8]. A positive correlation was detected between increased VEGF levels and lymph node involvement, and distant organ metastasis [9].
