TP53 and neoplasm: Interferon regulatory factor 1 (IRF1) is a transcription factor that acts as a regulator of immune responses and the cell cycle, as well as apoptosis in hematopoietic development.127,128 IRF1 was reported to act as a tumor suppressor, promoting cell cycle arrest or apoptosis induced by DNA damage either in cooperation with or independently of p53.129 SETD7 methylates IRF1 at K126.