ITPA and colorectal cancer: To confirm more precisely the contribution of MLH1 to the cell growth delay induced by ITPA deficiency, we performed ITPA KD in MLH1-deficient HCT116 cells, which are derived from human colorectal cancer cells, and MLH1-proficient H414 cells, which are derived from HCT116 cells as described in Supplementary Information (Figure S3).