VEGF-A as a prognostic indicator in advanced gastric and colorectal cancers and correlation with immune suppression involving myeloid-derived suppressor cells (MDSC).

250 Background: VEGF-A is important molecule should be controlled in cancer treatment since hypoxic and immunosuppressive conditions of tumor microenvironment are induced by VEGF-A. Myeloid-derived suppressor cells (MDSC), activated by chronic inflammation and VEGF-A, play critical roles in immunosuppression in patients with cancer. Methods: Serum levels of VEGF-A were measured by ELISA and circulating levels of MDSC were measured by Flow Cytometry (CD11b+, CD14-, CD33+). Patients with gastric and colorectal cancers were divided into two groups, high VEGF group (serum VEGF-A>330pg/ml) and lo group (≤330pg/ml). Results: Prognosis of stages III and IV gastric cancer with high VEGF-A was significantly worse than in low VEGF-A group, while difference was not significant in stages I and II. In colorectal cancer, the results were exactly same as found in gastric cancer. The levels of MDSC were significantly correlated with the levels of VEGF-A in patients with gastric and colorectal cancers. The levels of VEGF-A were also correlated with inflammatory markers including CRP and NLR (neutrophil to lymphocyte ratio), and inversely did to stimulation index of lymphocyte proliferation (SI: parameter of cellular immune reaction) and nutritional parameters such as albumin or rapid turnover protein. Conclusions: The observation in the present study suggest that VEGF-A is closely associated with inflammation-associated disease progression especially in advanced stages, and serve as useful marker of immunosuppression involving MDSC and prognosis in patients with gastric and colorectal cancers.