In the HPD group, there were fewer CD4+ effector T cells and CD8+ cytotoxic T cells (P <  0.010 and P <  0.382, respectively), whereas, there were significantly more regulatory T (Treg) cells co-expressing CD4+ and FOXP3+ in both the tumor and stroma (P <  0.003 and P <  0.015, respectively). Here, CD4 is linked to neoplasm.