title: Lineage switch in Philadelphia chromosome-positive acute lymphoblastic leukemia.
abstract: BACKGROUND
  An 8-year-old boy, initially diagnosed with Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL) (French-American-British [FAB]-L1), relapsed with Ph+ acute myelogenous leukemia (AML) (FAB-M2) 21 months after successful ALL treatment with standard therapy.
  
  
  METHODS
  The initial ALL presentation and subsequent AML relapse were analyzed by conventional morphologic, cytochemical, immunophenotypic, and cytogenetic studies.
  
  
  RESULTS
  Molecular analysis based on the polymerase chain reaction identified the presence of a bcr-I-abl fusion transcript at initial ALL presentation, the completion of ALL therapy, and AML relapse.
  
  
  CONCLUSIONS
  The cytogenetic and molecular results support a common clonal origin for this process. This is a case of lineage switch in a Ph+ acute leukemia. This case thus illustrates a manifestation of heterogeneous lineage differentiation among Ph+ acute leukemias.
authors.affiliation: Department of Pediatrics, University of Michigan Medical School, Ann Arbor 48109-0238.
authors.forename: D A
authors.initials: DA
authors.lastname: Reardon
authors.forename: C A
authors.initials: CA
authors.lastname: Hanson
authors.forename: M S
authors.initials: MS
authors.lastname: Roth
authors.forename: V P
authors.initials: VP
authors.lastname: Castle
mesh_terms: D001483:Base Sequence; D002648:Child; D016044:Fusion Proteins, bcr-abl / Q000032:analysis; D006801:Humans; D015464:Leukemia, Myelogenous, Chronic, BCR-ABL Positive / Q000235:genetics* / Q000473:pathology; D015470:Leukemia, Myeloid, Acute / Q000235:genetics* / Q000473:pathology; D008297:Male; D008969:Molecular Sequence Data; D010677:Philadelphia Chromosome; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000235:genetics* / Q000473:pathology
chemical_list: D016044:Fusion Proteins, bcr-abl