IL1B and neoplasm: We have demonstrated the role of host-derived IL-1 molecules on susceptibility to chemical carcinogenesis induced by 3-methylcholanthrene (3-MCA), which acts both as an initiator and a tumor promoter, using a battery of IL-1 KO mice [IL-1α−/−, IL-1β−/−, IL-1α/β−/−(double KO mice), or IL-1Ra−/−mice] in comparison to wild-type (WT) mice (51).