IL-33, together with its receptor ST2, seems to play a key role in the tumor environment by involving different pathways, such as interferon regulatory factor-3 (IRF-3), MyD88, AKT, COT, ERK, and JNK.IL-33 may act in both a pro- and antioncogenic way by increasing cells’ metabolism and by regulating the immune system [61,67] (Table 1). This evidence concerns the gene IL33 and neoplasm.