A Case Report of BCR-ABL-JAK2-Positive Chronic Myeloid Leukemia with Complete Hematological and Major Molecular Response to Dasatinib

Abstract

Chronic myeloid leukemia (CML) is a myeloproliferative neoplasm (MPN) that harbors the Philadelphia chromosomal translocation resulting in the uncontrolled production of mature granulocytes. Commonly, patients are diagnosed with CML during blood work for other reasons or enlarged spleen. The diagnosis is based on WHO criteria that require the demonstration of Philadelphia chromosome. Typically, <i>JAK2</i> mutation is not found in <i>BCR-ABL1</i>-positive MPN (CML). Most patients with CML are <i>JAK2</i> negative. It is rare for CML Philadelphia-positive patients to have a coexisting <i>JAK2</i> mutation. Little is known regarding the effect of <i>JAK2</i> mutation on the disease course of CML, the complications, and the response to treatment. We report the case of a 57-year-old man with no previous medical illness who presented with elevated white blood cell count on perioperative assessment for hernial repair; on further workup, he was diagnosed with Philadelphia-positive CML. He was found to have <i>JAK2</i> mutation and was started on treatment with dasatinib and achieved hematological and cytogenetic remission with loss of the <i>JAK2</i> mutation. Patients with <i>JAK2</i>-positive <i>BCR-ABL</i>-positive CML had a good hematological and cytogenetic response to dasatinib. In such rare coexistence of <i>JAK</i> and <i>BCR-ABL</i>, dasatinib is a good option due to multi-kinase activity.