Tumor immune escape is further favored by hypoxia-dependent release of lactic acid from tumor cells, which has been shown both to promote macrophage polarization towards the M2 subtype which secretes immunosuppressive cytokines and tumor-promoting soluble factors such as vascular endothelial growth factor (VEGF) [36], and to suppress the cytotoxic activity of CD8+ T cells [37]. This evidence concerns the gene VEGFA and neoplasm.