IL1RL1 and colorectal carcinoma: Using the AOM/DSS-induced model of CRC, we previously demonstrated that cytotoxic CD8+ T cells critically participate in antitumor immunity, and that ablation of FOXP3+ Tregs during intestinal tumorigenesis results in an increase of effector CD8+ T cells in the colon.19 Remarkably, we found a negative correlation between the frequency of ST2+ CD4+ FOXP3+ T cells and the frequency of CD8+ T cells in AOM/DSS-induced CRC lesions, thereby suggesting that IL-33/ST2 signaling adversely affects CD8+ T cell immunity during CRC (Fig. 6a).