title: [A study of mixed phenotype acute leukemia based on the 2008 World Health Organization classification].
abstract: BACKGROUND
  We evaluated the clinical significance of revised 2008 WHO classification needed to diagnose mixed phenotype acute leukemia (MPAL).
  
  
  METHODS
  A total of 22 MPAL patients, previously diagnosed by applying the scoring system of the European Group for Immunological Classification of Acute Leukemias (EGIL) were reclassified based on the 2008 WHO classification.
  
  
  RESULTS
  In 2008 WHO classification, the number of monoclonal antibodies (mAbs) required for assigning more than one lineage was markedly decreased, from 26 to 11, compared with that of EGIL. Seventeen of the 22 MPAL patients were reclassified as MPAL with following details: 6 MPAL with t(9;22)(q34;q11.2); BCR-ABL1, 1 MPAL with t(v;11q23); MLL rearranged, 7 MPAL, B/Myeloid, not otherwise specified (NOS) and 3 MPAL, T/Myeloid, NOS. Five patients were excluded from MPAL in the revised classification: 4 cytoplasmic myeloperoxidase (cMPO)-negative and 1 CD19-negative. The failure of complete remission achievement and occurrence of relapse were associated with poor prognosis (P=0.0002 and P=0.009, respectively). But the presence of Philadelphia chromosome was not significantly related with patient outcome (P=0.082). One patient with cCD79a, CD20, CD38, cMPO and CD15, whose diagnosis was reclassified from MPAL to AML has survived during the study period.
  
  
  CONCLUSIONS
  Because of decreased number of mAbs needed, it is possible that acute leukemia panel is designed to include all mAbs required to diagnose MPAL according to 2008 WHO classification. When diagnosing MPAL, it is critical to figure out positivity in either cMPO or CD19, and AML expressing more than 2 lymphoid antigens are considered as MPAL.
authors.affiliation: Department of Laboratory Medicine, The Catholic University of Korea, College of Medicine, Seoul, Korea.
authors.forename: Joonhong
authors.initials: J
authors.lastname: Park
authors.forename: Hyojin
authors.initials: H
authors.lastname: Chae
authors.forename: Myungshin
authors.initials: M
authors.lastname: Kim
authors.forename: Jihyang
authors.initials: J
authors.lastname: Lim
authors.forename: Yonggoo
authors.initials: Y
authors.lastname: Kim
authors.forename: Jaewook
authors.initials: J
authors.lastname: Lee
authors.forename: Nak Gyun
authors.initials: NG
authors.lastname: Chung
authors.forename: Bin
authors.initials: B
authors.lastname: Cho
authors.forename: Hack Ki
authors.initials: HK
authors.lastname: Kim
authors.forename: Seok
authors.initials: S
authors.lastname: Lee
authors.forename: Kyungja
authors.initials: K
authors.lastname: Han
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000368:Aged; D000911:Antibodies, Monoclonal / Q000276:immunology; D002648:Child; D002877:Chromosomes, Human; D005260:Female; D016044:Fusion Proteins, bcr-abl / Q000378:metabolism; D006801:Humans; D007223:Infant; D007938:Leukemia / Q000145:classification / Q000175:diagnosis* / Q000401:mortality; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D010677:Philadelphia Chromosome; D016019:Survival Analysis; D014944:World Health Organization
chemical_list: D000911:Antibodies, Monoclonal; D016044:Fusion Proteins, bcr-abl