Cytogenetic studies at diagnosis in polycythemia vera: clinical and JAK2V617F allele burden correlates.
ABSTRACT The prognostic significance of cytogenetic findings at diagnosis in polycythemia vera (PV) was investigated in a retrospective series of 137 patients. Cytogenetics were normal in 117 patients (85%) and displayed a -Y abnormality in five patients (7% of male patients), and other chromosomal abnormalities in 15 patients (11%). The most frequent cytogenetic anomalies were trisomy 8 (n = 4), trisomy 9 (n = 2), deletion 20q (n = 2) and chromosomal 1 abnormalities (n = 2). Parameters that were significantly associated with abnormal cytogenetics included age > or = 60 yr (P = 0.02), but not JAK2V617F allele burden, thrombosis, hemorrhage, leukemic/fibrotic transformation, or survival. We conclude that cytogenetic anomalies occur infrequently at PV diagnosis and do not confer an adverse outcome.
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ABSTRACT: Polycythemia vera, essential thrombocythemia, and primary myleofibrosis are chronic myeloproliferative neoplasms (MPNs) associated with an increased morbidity and mortality. MPNs are also associated with progression to acute myeloid leukaemia (AML) or myelodysplastic syndromes (MDS). The “true” rate of transformation is not known mainly due to selection bias in clinical trials and underreporting in population-based studies. The outcome after transformation is dismal. The underlying mechanisms of transformation are incompletely understood and in part remain an area of controversy. There is an intrinsic propensity in MPNs to progress to AML/MDS, the magnitude of which is not fully known, supporting a role for nontreatment-related factors. High doses of alkylating agents, P32 and combined cytoreductive treatments undoubtedly increase the risk of transformation. The potential leukemogenic role of hydroxyurea has been a matter of debate due to difficulties in performing large prospective randomized trials addressing this issue. The main focus of this review is to elucidate therapy-related leukemic transformation in MPNs with a special focus on the role of hydroxyurea.Bailliè re s Best Practice and Research in Clinical Haematology 06/2014; 27(2). DOI:10.1016/j.beha.2014.07.003 · 2.55 Impact Factor
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ABSTRACT: Background Polycythemia vera is the ultimate phenotypic consequence of the V617F mutation in Janus kinase 2 (encoded by JAK2), but the extent to which this mutation influences the behavior of the involved CD34+ hematopoietic stem cells is unknown. Methods We analyzed gene expression in CD34+ peripheral-blood cells from 19 patients with polycythemia vera, using oligonucleotide microarray technology after correcting for potential confounding by sex, since the phenotypic features of the disease differ between men and women. Results Men with polycythemia vera had twice as many up-regulated or down-regulated genes as women with polycythemia vera, in a comparison of gene expression in the patients and in healthy persons of the same sex, but there were 102 genes with differential regulation that was concordant in men and women. When these genes were used for class discovery by means of unsupervised hierarchical clustering, the 19 patients could be divided into two groups that did not differ significantly with respect to age, neutrophil JAK2 V617F allele burden, white-cell count, platelet count, or clonal dominance. However, they did differ significantly with respect to disease duration; hemoglobin level; frequency of thromboembolic events, palpable splenomegaly, and splenectomy; chemotherapy exposure; leukemic transformation; and survival. The unsupervised clustering was confirmed by a supervised approach with the use of a top-scoring-pair classifier that segregated the 19 patients into the same two phenotypic groups with 100% accuracy. Conclusions Removing sex as a potential confounder, we identified an accurate molecular method for classifying patients with polycythemia vera according to disease behavior, independently of their JAK2 V617F allele burden, and identified previously unrecognized molecular pathways in polycythemia vera outside the canonical JAK2 pathway that may be amenable to targeted therapy. (Funded by the Department of Defense and the National Institutes of Health.).New England Journal of Medicine 08/2014; 371(9):808-817. DOI:10.1056/NEJMoa1403141 · 54.42 Impact Factor
06/2014; 49(2):132-4. DOI:10.5045/br.2014.49.2.132