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Long-term survival and blast transformation in molecularly-annotated essential thrombocythemia, polycythemia vera and myelofibrosis.
Tefferi A, Guglielmelli P, Larson DR, Finke C, Wassie EA, Pieri L, Gangat N, Fjerza R, Belachew AA, Lasho TL, Ketterling RP, Hanson CA, Rambaldi A, Finazzi G, Thiele J, Barbui T, Pardanani A, Vannucchi AM.
Blood. 2014 Jul 18
JAK2 mutations define polycythemia vera (PV). CALR and MPL mutations are specific to JAK2-unmutated essential thrombocythemia (ET) and primary myelofibrosis (PMF). We examined the effect of these mutations on long-term disease outcome. 1581 patients from the Mayo Clinic (n=826) and Italy (n=755) were studied. Fifty-eight percent of Mayo patients were followed until death; median survivals were 19.8 years in ET (n=292), 13.5 PV (n=267; HR 1.8, 95% CI 1.4-2.2) and 5.9 PMF (n=267; HR 4.5, 95% CI 3.5-5.7). The survival advantage of ET over PV was not affected by JAK2/CALR/MPL mutational status. Survival in ET was inferior to the age- and sex-matched US population (p<0.001). In PMF (n=428), but not in ET (n=576), survival and blast transformation (BT) were significantly affected by mutational status; outcome was best in CALR-mutated and worst in triple-negative patients: median survival 16 vs 2.3 years (HR 5.1, 95% CI 3.2-8.0) and BT 6.5% vs 25% (HR 7.6, 95% CI 2.8-20.2), respectively. We conclude that life-expectancy in morphologically-defined ET is significantly reduced but remains superior to that of PV, regardless of mutational status. In PMF, JAK2/CALR/MPL mutational status is prognostically informative. Our observations do not support the concept of a disease continuum in JAK2-mutated myeloproliferative neoplasms.