Due to their distinct functions macrophages could be divided into (i) the M1 phenotype, which kill pathogens, promote the activation of cytotoxic CD8+ T cells and the differentiation of naïve CD4+ T cells into Th1 effector and Th17 cells and (ii) the M2 macrophages, which stimulate CD4+ Th2 cells as well as regulatory T cell differentiation and promote angiogenesis and tissue remodeling (pro-tumor functions). This evidence concerns the gene CD4 and neoplasm.