Among the components of PRC1.1, BCOR and BCLRL1, but not PCGF1 are targeted by somatic gene mutations in various hematological malignancies, including myelodysplastic syndrome (MDS), chronic myelomonocytic leukemia (CMML), and acute myeloid leukemia (AML) (Isshiki and Iwama, 2018). This evidence concerns the gene BCOR and chronic myelomonocytic leukemia.