JAK2V617F activating mutation is associated with the myeloproliferative type of chronic myelomonocytic leukaemia.
BACKGROUND
Chronic myelomonocytic leukaemia (CMML) is a haematopoietic malignancy with heterogeneous clinical and morphological features. It is classified in the World Health Organization myeloproliferative-myelodysplastic overlap category. JAK2(V617F) mutation can be found in a large percentage of patients with myeloproliferative neoplasms.


OBJECTIVE
To investigate the association between JAK2(V617F) mutation and clinical, haematological and bone marrow histological features in CMML and to verify whether the mutation is associated with the myeloproliferative type of the disease.


METHODS
78 consecutive patients with newly diagnosed CMML from 2004 to 2008 were included in the study. JAK2(V617F) mutation was assessed using direct sequencing of exon 14 or by allele-specific PCR from total peripheral blood or bone marrow samples.


RESULTS
JAK2(V617F) mutation was identified in eight cases (10.2%). All patients with the mutation presented with splenomegaly and had a significantly higher haemoglobin level and neutrophil count than patients without the mutation. All bone marrow biopsies of JAK2(V617F)-mutated CMML showed increased erythropoiesis, a marked myeloid and megakaryocytic hyperplasia with occasionally clustered megakaryocytes, and a mild or moderate (grade 1 or 2) fibrosis; six cases showed an increased number of dilated sinusoids and reactive lymphoid nodules.


CONCLUSIONS
The results indicate that JAK2(V617F) mutation is associated with clinical and morphological features of the myeloproliferative type of CMML. Therefore, JAK2 mutation analysis together with bone marrow morphology could help in a more appropriate classification of the disease.
Pich
A
A
Department of Biomedical Sciences and Human Oncology, Section of Pathology, University of Turin, Turin, Italy. achille.pich@unito.it
Riera
L
L
Sismondi
F
F
Godio
L
L
Davico Bonino
L
L
Marmont
F
F
Francia di Celle
P
P
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001706:Biopsy; D001853:Bone Marrow / Q000473:pathology; D004252:DNA Mutational Analysis / Q000379:methods; D004273:DNA, Neoplasm / Q000235:genetics; D005260:Female; D006801:Humans; D053614:Janus Kinase 2 / Q000235:genetics*; D015477:Leukemia, Myelomonocytic, Chronic / Q000097:blood / Q000235:genetics* / Q000473:pathology; D007958:Leukocyte Count; D008297:Male; D008875:Middle Aged; D009154:Mutation; D010976:Platelet Count
D004273:DNA, Neoplasm; C507924:JAK2 protein, human; D053614:Janus Kinase 2