Pathological evaluation of angiogenesis in human tumor

Angiogenesis is the process in which endothelial cells divide and migrate to form new capillaries, which support the continued growth of tumor through blood flow. Cancer-induced angiogenesis in general represents results of increased expression of angiogenic factors such as VEGF or decreased expression of anti-angiogenic factors, or a combination of both events. Numerous reported studies have demonstrated that angiogenesis plays an important role in tumor progression and metastasis of the great majority of human solid tumors. Furthermore, the quantitation of tumor angiogenesis in resected specimens of human tumor or surgical pathology specimens contribute to assessment of biological behavior and/or clinical outcome of the patients with cancer. Therefore, it is very important to assess the status of angiogenesis or cancer-induced vessels in resected tumor or surgical pathology specimens including those before and after the neoadjuvant therapy. It then becomes very important for pathologists involved in this evaluation to determine which methods to use in order to obtain accurate and reproducible results. In this short review, the status of an analysis of angiogenesis in surgical pathology specimens through analyzing vascular density or vasculatiry using immunohistochemical staining of CD34, a specific immunohistochemical marker for endothelial cells and subsequent evaluation of immunoreactivity in surgical pathology specimens will be summarized.