CD4 and malignant colon neoplasm: Not only is TGF-β pivotal for the suppression of gut inflammation and enhancing barrier function, but it also suppresses tumour progression in colon cancer and promotes the induction of functional Tregs from naive CD4+ T-cell precursors.62, 63 Interestingly, treatment with AIP-1 resulted in a significant increase in the frequency of CD4+CD25+Foxp3+ T cells in the colonic lamina propria.