title: Acute leukemias of ambiguous lineage.
abstract: The 2008 edition of the WHO Classification of Tumors of Haematopoietic and Lymphoid Tissues recognizes a special category called "leukemias of ambiguous lineage." The vast majority of these rare leukemias are classified as mixed phenotype acute leukemia (MPAL), although acute undifferentiated leukemias and natural killer lymphoblastic leukemias are also included. The major immunophenotypic markers used by the WHO 2008 to determine the lineage for these proliferations are myeloperoxidase, CD19, and cytoplasmic CD3. However, extensive immunophenotyping is necessary to confirm that the cells indeed belong to 2 different lineages or coexpress differentiation antigens of more than 1 lineage. Specific subsets of MPAL are defined by chromosomal anomalies such as the t(9;22) Philadelphia chromosome BCR-ABL1 or involvement of the MLL gene on chromosome 11q23. Other MPAL are divided into B/myeloid NOS, T/myeloid NOS, B/T NOS, and B/T/myeloid NOS. MPAL are usually of dire prognosis, respond variably to chemotherapy of acute lymphoblastic or acute myeloblastic type, and benefit most from rapid allogeneic hematopoietic stem cell transplantation.
authors.affiliation: Laboratoire d'Immunologie du CHU and Nancy Université, Vandoeuvre lès Nancy, France.
authors.forename: Marie C
authors.initials: MC
authors.lastname: Béné
authors.forename: Anna
authors.initials: A
authors.lastname: Porwit
mesh_terms: D018941:Antigens, CD19 / Q000378:metabolism; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D014408:Biomarkers, Tumor / Q000378:metabolism; D017252:CD3 Complex / Q000378:metabolism; D019070:Cell Lineage; D002869:Chromosome Aberrations; D005434:Flow Cytometry; D015321:Gene Rearrangement; D018380:Hematopoietic Stem Cell Transplantation; D006801:Humans; D015456:Leukemia, Biphenotypic, Acute / Q000145:classification* / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D008214:Lymphocytes / Q000378:metabolism / Q000473:pathology; D009195:Peroxidase / Q000378:metabolism; D011379:Prognosis; D014944:World Health Organization
chemical_list: D018941:Antigens, CD19; D014408:Biomarkers, Tumor; D017252:CD3 Complex; D009195:Peroxidase