CD4 and neoplasm: A375 or patient-derived tumor xenograft (PDX)-bearing mice treated with a-CTLA4-TGFβRII exhibited a significant reduction of tumor-infiltrating Tregs (CD4+CD25+CD127lowFOXP3+ cells) compared to those treated with a-CTLA-4 (p < 0.001 for A375, p < 0.003 for PDX1, and p < 0.02 for PDX2; Student’s unpaired t-test) (Fig. 3c).