For instance, Treg cells infiltrated in CRC are enriched for less immunosuppressive Foxp3lo population rather than more immunosuppressive Foxp3hi subset.547 Th17 cell-mediated pro-inflammatory and pro-tumor responses in CRC can be attenuated by Treg cells.548 In addition, Treg cells in CRC can also be induced to express pro-inflammatory cytokines including IL-17, IFN-γ, and TNF-α, exerting an anti-tumor immunity.549,550 Therefore, high Treg cells together with a low frequency of CD8+ CTLs are better prediction for unfavorable prognosis in various types of cancer.542,551. This evidence concerns the gene CD8A and colorectal carcinoma.