Insulin significantly promotes human colon cancer HT-29 cells to proliferate and migrate.27 Furthermore, accumulating evidence shows that the influence of insulin on tumor growth is carried out by changing the expression of oncogenes or tumor suppressor genes, like insulin-induced programmed death ligand 1 (PD-L1) expression in pancreatic ductal adenocarcinoma (PDAC) cells, thus suppressing the activity of CD8+T cells in PDAC.27 As Heckl et al28 revealed, insulin promotes the progression of colon cancer by up-regulating the expression of ACAT1. Here, CD8A is linked to malignant colon neoplasm.