IL1R1 and neoplasm: In addition, IL-1 cytokines exert important immunomodulatory functions in the tumor microenvironment, where IL-1α and IL-1β derived from tumor cells and/or tumor-associated macrophages act on IL-1 receptor (IL-1R)-expressing cells, including cancer-associated fibroblasts (CAFs), with the secretion of several tumor-promoting cytokines (including IL-6, IL-8, and transforming growth factor (TGF)-β) [15,16,17,18] and CD4+ T helper (Th) cell effectors [19].