Janus kinase 2 V617F mutation is detectable in spleen of patients with chronic myeloproliferative diseases suggesting a malignant nature of splenic extramedullary hematopoiesis.
Extramedullary hematopoiesis occurs in patients with a variety of hematologic diseases, and the spleen is a common site. Extramedullary hematopoiesis is very common in chronic myeloproliferative diseases and myeloproliferative/myelodysplastic diseases. The pathogenesis of extramedullary hematopoiesis is unknown. Using JAK2 V617F mutation as a molecular marker, we assessed paired spleen and bone marrow samples of 15 patients with various types of chronic myeloproliferative diseases and myeloproliferative/myelodysplastic diseases. The diagnosis was chronic idiopathic myelofibrosis (n=8), polycythemia vera (n=3), and chronic myelomonocytic leukemia (n=4). DNA was extracted from fixed, paraffin-embedded tissue and assessed for JAK2 V617F by real-time polymerase chain reaction assay followed by melting curve analysis. Concordant JAK2 mutation was detected in the paired samples in 7 patients. A discordant result with JAK2 V617F found in the spleen but not bone marrow was noted in 1 patient. These results indicate that extramedullary hematopoiesis in patients with chronic myeloproliferative diseases and myeloproliferative/myelodysplastic diseases is a clonal process and lend support to the theory that the cells of extramedullary hematopoiesis are carried from the bone marrow.
Konoplev
Sergej
S
Department of Hematopathology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA. skonople@mdanderson.org
Hsieh
Pin-Pen
PP
Chang
Chung-Che
CC
Medeiros
L Jeffrey
LJ
Lin
Pei
P
D000328:Adult; D000368:Aged; D001853:Bone Marrow / Q000503:physiopathology*; D002869:Chromosome Aberrations; D005260:Female; D006411:Hematopoiesis, Extramedullary; D006801:Humans; D053614:Janus Kinase 2 / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D009154:Mutation; D009196:Myeloproliferative Disorders / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013154:Spleen / Q000503:physiopathology*
D053614:Janus Kinase 2