Because an increase in cell proliferation can enhance the cytotoxic effect of 6MP [38], we compared the growth rate of the modified cells, and observed no difference between NUDT15‐KD cells and the scramble control in terms of cell proliferation assay as well as subcutaneous tumor with mouse model (Figure S10F–H), indicating that the increase in sensitivity to 6MP is primarily dependent on the KD‐induced loss of NUDT15 activity. This evidence concerns the gene NUDT15 and neoplasm.