title: Multiparameter analysis of acute mixed lineage leukemia: correlation of a B/myeloid immunophenotype and immunoglobulin and T-cell receptor gene rearrangements with the presence of the Philadelphia chromosome translocation in acute leukemias with myeloid morphology.
abstract: Morphological, immunological, cytogenetic, and molecular features of 28 cases of acute mixed lineage leukemia (AMLL), defined by the co-expression of lymphoid and myeloid cell surface antigens, were correlated in a multiparameter study. These 28 cases were identified in a series of 260 consecutive acute leukemia cases occurring predominantly in adults and were subdivided into 18 cases of AMLL with myeloid morphology and cytochemistry (AMLL-AML) and 10 cases of AMLL with lymphoid morphology and cytochemistry (AMLL-ALL). A lack of correlation was observed between the expression of B- or T-cell associated antigens with the presence of the expected immunoglobulin (Ig) or T-cell receptor (TCR) gene rearrangements in the AMLL cases with myeloid morphology. Only three of the 18 total AMLL-AML cases, each co-expressing B- and myeloid-associated cell surface antigens (B/My), had Ig heavy chain gene rearrangements with or without rearrangements of TCR genes. Ig light chain genes remained in the germline configuration. Strikingly, these three cases were the only AMLL-AML cases in our series to have the Philadelphia (Ph) chromosome translocation t(9;22)(q34;q11), suggesting that a significant percentage of acute leukemias with myeloid morphology and gene rearrangements may be Ph+ AMLL. The fact that three of the 10 B/My AMLL-AML cases in our series were Ph+ suggests that there may be an increased frequency of Ph chromosome, a translocation associated with a poor prognostic outcome, in B/My AMLL-AML occurring in the adult population. Although most AMLL cases with lymphoid morphology had Ig and TCR gene rearrangements associated with a variety of immunophenotypes and karyotypes, two Ph+ AMLL-ALL cases had many similar features (B/My immunophenotype; IgH with or without TCR rearrangements; Ig light chain genes germline) to their Ph+ AMLL-AML counterparts. However, the Ph+ AMLL-ALL cases differed from the Ph+ AMLL-AML cases by the expression of a more mature B-cell lineage immunophenotype and by their additional cytogenetic changes.
authors.affiliation: Department of Pathology, University of New Mexico School of Medicine, Albuquerque.
authors.forename: I A
authors.initials: IA
authors.lastname: Saikevych
authors.forename: D P
authors.initials: DP
authors.lastname: Kerrigan
authors.forename: T S
authors.initials: TS
authors.lastname: McConnell
authors.forename: D R
authors.initials: DR
authors.lastname: Head
authors.forename: F R
authors.initials: FR
authors.lastname: Appelbaum
authors.forename: C L
authors.initials: CL
authors.lastname: Willman
mesh_terms: D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D002648:Child; D002675:Child, Preschool; D005260:Female; D015321:Gene Rearrangement / Q000235:genetics; D015329:Gene Rearrangement, T-Lymphocyte / Q000235:genetics*; D006801:Humans; D007136:Immunoglobulins / Q000235:genetics*; D016130:Immunophenotyping; D007223:Infant; D015456:Leukemia, Biphenotypic, Acute / Q000235:genetics*; D007951:Leukemia, Myeloid / Q000145:classification / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D010677:Philadelphia Chromosome; D014178:Translocation, Genetic / Q000235:genetics*
chemical_list: D007136:Immunoglobulins