Similarly, tamoxifen‐induced Prmt1 deletion significantly prolonged the survival (median survival: Prmt1fl/fl vs Prmt1fl/fl; Cre‐ERT2 was 20 days vs not reached after monitoring for 60 days; Figure S3C, Supporting Information), obviously alleviated the splenomegaly and spleen weight (Figure S3D,E, Supporting Information), reduced the leukemia burden and percentages of LSPCs in BM and spleen of CML mice (Figure S3F–M, Supporting Information). Here, MAPK3 is linked to chronic myelogenous leukemia, BCR-ABL1 positive.