Mixed-phenotype acute leukemia: historical overview and a new definition

• Published in: Leukemia Vol. 24; no. 11; pp. 1844 - 1851
• Main Authors: Weinberg, O K, Arber, D A
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 01.11.2010; Nature Publishing Group
• Subjects: 631/67/1059; 692/699/67/1990/283; 692/700/139; Acute Disease; Acute leukemia; Acute lymphoblastic leukemia; Acute myeloid leukemia; Algorithms; Antibodies; Antigens, CD - analysis; Biological and medical sciences; Biomarkers, Tumor - analysis; Blast Crisis - pathology; Cancer; Cancer Research; Care and treatment; Clinical aspects; Criteria; Critical Care Medicine; Development and progression; Gene Rearrangement; Genetic aspects; Genotype & phenotype; Health aspects; Hematologic and hematopoietic diseases; Hematology; Humans; Immunology; Intensive; Internal Medicine; Leukemia; Leukemia - classification; Leukemia - epidemiology; Leukemia - genetics; Leukemia, B-Cell - classification; Leukemia, B-Cell - genetics; Leukemia, T-Cell - classification; Leukemia, T-Cell - genetics; Leukemias. Malignant lymphomas. Malignant reticulosis. Myelofibrosis; Lymphatic leukemia; Markers; Medical diagnosis; Medical sciences; Medicine; Medicine & Public Health; Morphology; Oncology; Phenotype; Phenotypes; Rare diseases; review; Tumors; United States; United States > US; biphenotypic leukemia; diagnosis; mixed-phenotype acute leukemia; review; Phenotype; Hematology; Mixed; Definition; Acute leukemia; Malignant hemopathy; Review; Diagnosis; Bibliographic review; Cancer
• ISSN: 0887-6924; 1476-5551
• DOI: 10.1038/leu.2010.202

Acute leukemia with a mixed phenotype is a rare disease and comprises 2–5% of all acute leukemias. These disorders have been known historically by a variety of names, such as mixed lineage leukemia, bilineal leukemia and biphenotypic leukemia, and the criteria for diagnosis have often been arbitrary. The scoring criteria proposed by the European Group for the Immunological Characterization of Leukemias represented a major attempt to define this disorder. However, the relative weight given to some markers and the lack of lineage specificity of most markers have raised questions regarding the significance of this approach. In 2008, the World Health Organization classification of hematopoietic and lymphoid tumors proposed a simpler diagnostic algorithm, which relies on fewer and more lineage-specific markers to define mixed-phenotype acute leukemia (MPAL). MPAL with t(9;22) and MLL rearrangement have been separated. Several studies have suggested that patients with acute leukemia of mixed phenotype have a worse clinical outcome when compared with matched controls with acute myeloid leukemia or acute lymphoblastic leukemia. Further studies are needed to confirm the significance of MPAL as currently defined, to determine a standardized treatment approach and to better understand the biological and clinical aspects of this disease.