Evidence from mice and humans suggests an anti‐tumourigenic role for Ifng in colorectal cancer (CRC), as a loss of type 1 cytokines accompanies the adenoma–carcinoma sequence in the colorectum18; intestinal tumourigenesis is promoted in mice deficient for Ifng or its receptors19; and Th1 cytokines lead to cancer senescence20. The gene discussed is IFNG; the disease is carcinoma.