SF3B1-mutant myelodysplastic syndrome as a distinct disease subtype - A Proposal of the International Working Group for the Prognosis of Myelodysplastic Syndromes (IWG-PM)

The 2016 revision of the World Health Organization (WHO) classification of tumors of hematopoietic and lymphoid tissues is characterized by a closer integration of morphology morphology: The study of the structure and form of an organism or one of its parts. and molecular genetics. Notwithstanding, the myelodysplastic syndrome (MDS) with isolated del(5q) remains so far the only MDS subtype defined by a genetic abnormality. About half of MDS patients carry somatic mutations in spliceosome genes, with SF3B1 being the most commonly mutated one. SF3B1 mutation mutation: Any change or alteration in a gene. A mutation may cause disease or may be a normal variation. Paroxysmal nocturnal hemoglobinuria (PNH) occurs because of a mutation in the PIG-A gene of a single stem cell in the bone marrow. identifies a condition characterized by ring sideroblasts, ineffective erythropoiesis, and indolent clinical course. A large body of evidence supports recognition of SF3B1-mutant MDS as a distinct nosologic entity. To further validate this notion, we interrogated the dataset of the International Working Group for the Prognosis of MDS (IWG-PM). Based on the findings of our analyses, we propose the following diagnostic criteria for SF3B1-mutant MDS: (i) cytopenia cytopenia: (sie-tuh-PEE-nee-uh) A shortage of one or more blood cell types. Also called a low blood count. as defined by standard hematologic values; (ii) somatic SF3B1 mutation; (iii) morphologic dysplasia (with or without ring sideroblasts); (iv) bone marrow bone marrow: The soft, spongy tissue inside most bones. Blood cells are formed in the bone marrow. blasts blasts: See Blast Cells. <5% and peripheral blood blasts <1%. Selected concomitant genetic lesions represent exclusion criteria for the proposed entity. In patients with clonal cytopenia of undetermined significance, SF3B1 mutation is almost invariably associated with subsequent development of overt MDS with ring sideroblasts, suggesting that this genetic lesion provides presumptive evidence of MDS in the setting of persistent unexplained cytopenia. Diagnosis of SF3B1-mutant MDS has considerable clinical implications in terms of risk stratification and therapeutic decision making. In fact, this condition has a relatively good prognosis and may respond to luspatercept with abolishment of transfusion requirement.