CD4 and diffuse large B-cell lymphoma: who reported that infiltration by both the Foxp3+CD4+ and PD-1+CD4+ T cell subsets was correlated with the prognosis of patients with diffuse large B-cell lymphoma (53), and Suresh et al., who found that PD-1+ and Foxp3+ T cell reduction might correlate with survival and serve as a predictive biomarker for hepatocellular carcinoma patients undergoing sorafenib therapy (54).