Presence of Additional Cytogenetic Abnormality of t(1;15) at Diagnosis of Chronic Myelogenous Leukemia-Chronic Phase.

At diagnosis, fewer than 10% of chronic myelogenous leukemia (CML) patients have additional cytogenetic abnormalities (ACAs), which are frequently found in transformation to blast crisis. We report a case of CML-chronic phase (CML-CP) that showed t(1;15) at diagnosis. A 64-year-old man presented with sustained leukocytosis and thrombocytosis. His bone marrow (BM) was hypercellular with 2.5% blasts and BCR-ABL1 rearrangement. The karyotype in the BM was 46,XY,t(1;15)(q32;p13),t(9;22)(q34;q11.2)[20], while the karyotype in the peripheral blood was 46,XY[20]. This is the first report on the presence of t(1;15) at diagnosis of CML-CP, and its clinical significance remains unclear.