APOE and cancer: Mechanistically, tumor-associated macrophages (TAMs) are the primary regulators of the local immunosuppressive environment in cancer stroma [80] and, accordingly, they were found to have increased the expression of ApoE in pancreatic cancer cells, which in turn lead to the expression of two chemokines, i.e., CXCL1 and CXCL5, by pancreatic cancer cells [78].