ASXL1 and myelodysplastic syndrome: –Secondary evolution to MDS–Critical drivers of clonal evolution are compensatory proliferation in the hypocellular marrow and immune escape (64)–Characteristic clonal findings: PNH clones with PIGA mutations, deletion of (antigenic) HLA alleles by loss of the chromosomal arm 6p or typical MDS mutations (ASXL1, DNMT3A, TET2, and others) (80–82)