CD4 and neoplasm: A reduction of CD4+CD25+ cells, as well as of TGF-β and IL-6 production, was observed in group P compared to group T. IL-6 is known to promote tumor growth by upregulating anti-apoptotic and pro-angiogenic proteins in tumor cells [14], and TGF-β is known to support tumor progression by promoting cell invasion and dissemination to distant sites, enhancing angiogenesis and mediating the immune evasion of tumor cells [15].