Novel mutations and their functional and clinical relevance in myeloproliferative neoplasms: JAK2, MPL, TET2, ASXL1, CBL, IDH and IKZF1.
Myeloproliferative neoplasms (MPNs) originate from genetically transformed hematopoietic stem cells that retain the capacity for multilineage differentiation and effective myelopoiesis. Beginning in early 2005, a number of novel mutations involving Janus kinase 2 (JAK2), Myeloproliferative Leukemia Virus (MPL), TET oncogene family member 2 (TET2), Additional Sex Combs-Like 1 (ASXL1), Casitas B-lineage lymphoma proto-oncogene (CBL), Isocitrate dehydrogenase (IDH) and IKAROS family zinc finger 1 (IKZF1) have been described in BCR-ABL1-negative MPNs. However, none of these mutations were MPN specific, displayed mutual exclusivity or could be traced back to a common ancestral clone. JAK2 and MPL mutations appear to exert a phenotype-modifying effect and are distinctly associated with polycythemia vera, essential thrombocythemia and primary myelofibrosis; the corresponding mutational frequencies are approximately 99, 55 and 65% for JAK2 and 0, 3 and 10% for MPL mutations. The incidence of TET2, ASXL1, CBL, IDH or IKZF1 mutations in these disorders ranges from 0 to 17%; these latter mutations are more common in chronic (TET2, ASXL1, CBL) or juvenile (CBL) myelomonocytic leukemias, mastocytosis (TET2), myelodysplastic syndromes (TET2, ASXL1) and secondary acute myeloid leukemia, including blast-phase MPN (IDH, ASXL1, IKZF1). The functional consequences of MPN-associated mutations include unregulated JAK-STAT (Janus kinase/signal transducer and activator of transcription) signaling, epigenetic modulation of transcription and abnormal accumulation of oncoproteins. However, it is not clear as to whether and how these abnormalities contribute to disease initiation, clonal evolution or blastic transformation.
Tefferi
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Division of Hematology, Department of Medicine, Mayo Clinic, Rochester, MN 55905, USA. tefferi.ayalew@mayo.edu
D014408:Biomarkers, Tumor / Q000235:genetics* / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics; D049308:Dioxygenases; D006801:Humans; D051740:Ikaros Transcription Factor / Q000235:genetics; D007521:Isocitrate Dehydrogenase / Q000235:genetics; D053614:Janus Kinase 2 / Q000235:genetics; D009154:Mutation / Q000235:genetics*; D009196:Myeloproliferative Disorders / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D009363:Neoplasm Proteins / Q000235:genetics* / Q000378:metabolism; D011379:Prognosis; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins / Q000235:genetics; D050721:Proto-Oncogene Proteins c-cbl / Q000235:genetics; D053628:Receptors, Thrombopoietin / Q000235:genetics; D012097:Repressor Proteins / Q000235:genetics
C473949:ASXL1 protein, human; D014408:Biomarkers, Tumor; D004268:DNA-Binding Proteins; C497239:IKZF1 protein, human; C000715470:MAS1 protein, human; D009363:Neoplasm Proteins; D000090063:Proto-Oncogene Mas; D011518:Proto-Oncogene Proteins; D053628:Receptors, Thrombopoietin; D012097:Repressor Proteins; C082218:MPL protein, human; D051740:Ikaros Transcription Factor; D007521:Isocitrate Dehydrogenase; C543588:IDH1 protein, human; D049308:Dioxygenases; C541081:TET2 protein, human; D050721:Proto-Oncogene Proteins c-cbl; C507924:JAK2 protein, human; D053614:Janus Kinase 2; C067419:CBL protein, human