In colorectal cancer, MSCs release PGE-2 in response to IL-1 secreted by tumor cells, PGE-2 in an autocrine fashion promotes the expression of IL-8, IL-6, CXCL1, RANTES, and GRO-α, which together stimulate the formation of CSCs (20). The gene discussed is CXCL1; the disease is colorectal cancer.