RUNX1 and chronic myelogenous leukemia, BCR-ABL1 positive: In the case of KRAS, de novo mutation acquisition was proven in the clone bearing mutations in ATRX and RUNX1. While KRAS mutations in CML seem to be particularly rare events (22), it should be noted that the pattern of acquisition of a KRAS mutation following RUNX1 genetic lesions was described in AML (23).