MAPK3 and chronic myelogenous leukemia, BCR-ABL1 positive: Consistently, the proportions of leukemia cells (T315I‐BCR‐ABL‐GFP+), myeloid cells (T315I‐BCR‐ABL‐GFP+Gr1+), LSPCs including T315I‐BCR‐ABL‐GFP+LSK cells, T315I‐BCR‐ABL‐GFP+LT‐HSCs and T315I‐BCR‐ABL‐GFP+ST‐HSCs, as well as T315I‐BCR‐ABL‐GFP+GMP and T315I BCR‐ABL‐GFP+CMP cells was significantly lower in BM and spleen of Prmt1fl/fl; Cre‐ERT2 CML mice than Prmt1fl/fl CML mice (Figure S5E–K, Supporting Information).