To investigate the activation of MMR in SETD2/H3K36me3‐deficient CML cells, immunofluorescence was used to check for MSH6 foci, since MSH6 is one of the partners of the hMutSα heterodimeric complex whose role is to recognize base–base mismatches or small indels and trigger MMR. The gene discussed is MRC1; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.