Concomitant presence of JAK2V617F mutation and BCR-ABL translocation in two patients: A new entity or a variant of myeloproliferative neoplasms (Case report)

Myeloproliferative neoplasms (MPNs) are classically divided into BCR RhoGEF and GTPase activating protein (BCR)-ABL proto-oncogene 1 non-receptor tyrosine kinase (ABL) positive chronic myeloid leukemia (CML) and BCR-ABL negative MPNs, including essential thrombocythemia (ET). One of the major diagnostic criteria for ET is the absence of the philadelphia chromosome, thus when present it is almost indicative of CML. ET and CML are considered to be mutually exclusive; however, there are rare situations in which patients with ET present positive BCR-ABL without the features of CML. Although from the literature review, the frequency of JAK2V617F mutation and BCR-ABLtranslocation coexistence in MPNs is low, it may be higher than expected. The current study reported cases of two patients with an initial diagnosis of ET in the presence of JAK2V617F mutation and BCR-ABL translocation by fluorescent in situ hybridization. Both patients presented with a heterozygous BCR-ABL translocation, and absence of p190 and p210 transcripts, seemingly a der(9) in the background of an ET JAK2V617F mutation.