CD4 and neoplasm: Additionally, tumor-bearing mice had significantly higher proportions of CD4+ cells in the blood compared to non-tumor controls Huang et al. reported that CD4+ cells are significantly increased in the blood of 4T1 tumor bearing animals with advancing tumor stages and that these cells progressively change their differentiation status from anti-tumor Th1’s to pro-tumor T regulatory (Treg) cells and Th17 cells [29].