title: Diagnosis of biphenotypic acute leukemia: a paradigmatic approach.
abstract: Biphenotypic acute leukemia (BAL), or acute leukemia with a single population of blasts coexpressing markers of two different lineages, is a rare clinical entity. To define BAL, a scoring system was proposed by the European Group of Immunological Markers for Leukemias (EGIL) in 1995. However, increasing evidence suggests that this system has limitations, as acknowledged by the 2008 World Health Organization (WHO) Classification of Tumors of Hematopoietic and Lymphoid Tissues. Although substantially improved in relation to the EGIL, the new WHO Classification is still not optimal for guiding the clinical management of patients with BAL. We propose a new paradigmatic approach to defining BAL based on recent clinical studies of BAL and advances in immunologic marker definition and cytogenetics, and applied our new approach to 8 cases of "BAL" among a cohort of 742 new acute leukemias in our Cancer Center. By our new criteria, 6 cases were reclassified as acute lymphoblastic leukemia (ALL), while only 2 were still classified as BAL. Our approach is also supported by analyses of the BAL cases previously reported by other institutions.
authors.affiliation: Department of Pathology, University of Maryland School of Medicine, Marlene and Stewart Greenebaum Cancer Center, Baltimore, MD 21201, USA. xzhao@umm.edu
authors.forename: Xianfeng Frank
authors.initials: XF
authors.lastname: Zhao
authors.forename: Ivana
authors.initials: I
authors.lastname: Gojo
authors.forename: Teresa
authors.initials: T
authors.lastname: York
authors.forename: Yi
authors.initials: Y
authors.lastname: Ning
authors.forename: Maria R
authors.initials: MR
authors.lastname: Baer
mesh_terms: D000293:Adolescent; D000328:Adult; D000369:Aged, 80 and over; D000951:Antigens, Neoplasm / Q000032:analysis; D014408:Biomarkers, Tumor / Q000235:genetics / Q000276:immunology; D002648:Child; D005260:Female; D006801:Humans; D016130:Immunophenotyping; D015456:Leukemia, Biphenotypic, Acute / Q000145:classification / Q000175:diagnosis* / Q000235:genetics / Q000276:immunology; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D012189:Retrospective Studies; D014944:World Health Organization; D055815:Young Adult
chemical_list: D000951:Antigens, Neoplasm; D014408:Biomarkers, Tumor