Evidence for BCR/ABL1‐positive T‐cell acute lymphoblastic leukemia arising in an early lymphoid progenitor cell

Abstract

BCR‐ABL1‐positive leukemias have historically been classified as either chronic myelogenous leukemia or Ph+ acute lymphoblastic leukemia. Recent analyses suggest there may be a wider range of subtypes. We report a patient with BCR‐ABL1 fusion positive T‐cell ALL with a previously undescribed cell distribution of the fusion gene. The examination of sorted cells by fluorescence in situ hybridization showed the BCR‐ABL1 fusion in the malignant T cells and a subpopulation of the nonmalignant B cells, but not nonmalignant T cells or myeloid or CD34+ progenitor cells providing evidence that the fusion may have occurred in an early lymphoid progenitor.