Carcinogen-induced CRC caused by serial (n = 8) treatments with AOM, in absence of DSS treatment20 (Fig. 1H) was not impacted in Irf1−/− mutants with respect to number and size of tumors (at end of week 18; Fig. 1I), in comparison with the resistant B6 and susceptible A/J mice. The gene discussed is IRF1; the disease is infectious otitis media.