IRF9 and colitis: However, we found no consistent differences in the activation of cell death components (gasdermin D and gasdermin E, CASP3, CASP7, and CASP8) at day 14 in the colons of AOM/DSS-treated WT and Irf9−/− mice (Supplemental Figure S1), suggesting that reduced tumor burden in Irf9−/− mice is due to the role of IRF9 in colitis and not in colonic cell death regulation in response to AOM/DSS.