Indeed, although the role of the IL-33 and ST2 interplay in cancer has not been fully elucidated, it appears that IL-33 signaling can have both beneficial effects in certain experimental tumors,42,43 while in other studies it has been reported that IL-33 contributes to GBM tumorigenesis.17,33,34,44 IL-33 could thus be associated with tumor progression,7,9,34 or, alternatively, part of an alarmin response to a growing tumor. This evidence concerns the gene IL1RL1 and cancer.