IDO1 and neoplasm: Short‐term radiation therapy induces oncogenic AF1q expression in rectal cancer that correlates with negative lymph node stage AF1q expression associates with high STAT1 and low IDO1 expression in irradiated tumor samples The favorable effects of short‐term radiation therapy on tumor biology might be enhanced by an AF1q‐driven pro‐apoptotic signaling axis AF1q may be a promising therapeutic target responsive to radiation therapy.