Atypical chronic myeloid leukemia with t(9;22)(p24,11.2), a BCR-JAK2 fusion gene
In April 2010, a 54-year-old male patient presented with fatigue, abdominal pain and splenomegaly. A blood count revealed leukocytosis (93.38 x 109/L) with a predominance of neutrophils and a shift to the left. Hypercellular bone marrow with granulocytic and erythroid dysplasia was described. Conventional cytogenetic analysis was performed and a 46,XY,t(9;22) (p24;q11.2) karyotype was found in 90% of the metaphases examined ( 1) In view of the clinical picture, the result was interpreted as indicative of the presence of a BCR-ABL1 fusion gene, but this was not detected by reverse transcription polymerase chain reaction (RT-PCR). The presence of a BCR-ABL rearrangement was also ruled out by fluorescence in situ hybridization (FISH) using a BCR-ABL probe. In addition, no BCR/PDGFR FIP fusion gene or JAK2 V617F mutation were detected by RT-PCR. Therefore, the case was classified, according to the latest World Health Organization Classification, as BCR-ABL1-negative atypical CML.\nThe patient was treated with imatinib at a dose of 400 mg/day because of the involvement of the BCR gene. After three months of treatment, he presented weight loss, progressive splenomegaly and no hematologic response. His medication was changed to dasatinib (150 mg/day) plus hydroxyurea (3 g/day). In August 2011, given the absence of a hematologic response, the dasatinib treatment was discontinued.\nConventional karyotyping was performed again and the 46,XY,t(9;22)(p24;q11.2) karyotype was observed in all metaphases examined.\nIn October 2012, the patient had not achieved complete hematologic remission with hydroxyurea. However, in the meantime, his sister had been identified as an HLA-fully matched donor and he was presenting a 90% Karnofsky score. Thus, he was referred for an allogeneic bone marrow transplant. Fifty-three days after the transplantation he died due to acute graft-versus-host disease affecting his gastrointestinal tract and skin.