To meet diagnostic criteria, MDS patients with SF3B1 mutations must have <5% in the bone marrow and <2% in the peripheral blood and must not carry specific cytogenetic and molecular abnormalities, including isolated del(5q), −7/del(7q), abn3q26.2, or complex karyotype, TP53 multi-hit, or RUNX1 mutations [47]. Here, RUNX1 is linked to myelodysplastic syndrome.