Philadelphia-positive case negative for JAK2 V617F mutation with hyperdiploidic karyotype: A case report

Chronic myeloid leukemia (CML) is one of the most common hematological malignancies and accounts for 15-20% of all leukemia cases. The cytogenetic marker of CML is the presence of Philadelphia chromosome (Ph) in >95% of patients. The current case reports a 83-year old woman who was directed to the genetic laboratory for a cytogenetic and molecular-genetic analysis suspected to be Ph positive [(+)]. Karyotype analysis of a bone marrow sample revealed a hyperdiploid karyotype in a part of Ph (+) cells with additional chromosomes 8, 10 and 12. Restriction analysis for V617F JAK2 mutation was negative, while the quantitative RT-qPCR assay indicated BCR-ABL/ABL transcript at the level of 120% International Scale (IS). Generally cytogenetic complexities are important in the prognostic evaluation of CML. Besides the Ph chromosome, a variet of chromosomal aberrations may be associated with CML. A total of 5-10% of these cases show complex translocations involving another chromosome. The current case is Ph(+) demonstrating an additional hyperdiploid karyotype clone with three additional autosomes (8, 10 and 12). This case highlights the significance of cytogenetic abnormalities on the prognosis of CML.