CD4 and neoplasm: While analyzing the safety of surgery and the immune phenotype of the resected tumors under Ipilimumab, Gyorki et al. reported an increase in CD4+Foxp3+ T-regulatory cell proportion and a 2.8-fold lower CD8+/CD4+Foxp3+ ratio in the tumor compared with the blood, in progressive tumors, suggesting a possible mechanism of immune escape [25].