title: A comparative analysis of cytoplasmic mu (C mu) expression in acute lymphoblastic leukemia by molecular and immunologic techniques. Identification of leukemia cases expressing C mu mRNA transcripts in the absence of detectable C mu proteins.
abstract: Among acute lymphoblastic leukemias derived from the B-cell lineage, the subset of cases expressing cytoplasmic mu heavy chain proteins (C mu) in the absence of surface immunoglobulin has been designated pre-B-cell acute lymphoblastic leukemia. This group, traditionally identified using immunologic smear techniques, has been associated with a poor prognosis in some series. In a comparative study, 25 cases of B-lineage acute lymphoblastic leukemia were analyzed for C mu expression using molecular and immunologic techniques. RNA derived from cryopreserved blast cells was hybridized in both Northern and slot-blot analyses using a probe (pBZ311) containing four exons of the human immunoglobulin heavy chain mu constant region gene. Expression of C mu proteins was assessed simultaneously by slide immunofluorescence and flow cytometric techniques in all samples. These studies were correlated with immunoglobulin heavy and light chain gene rearrangements, cell-surface immunophenotype, cytogenetics, and other clinicopathologic features. C mu mRNA transcripts were detected in 14 of 25 cases, whereas C mu proteins were detected in only 9 of these cases using flow cytometric techniques. Only four of these nine cases were positive by slide immunofluorescence techniques. These studies imply that molecular and flow cytometric techniques may be a more sensitive means to assess C mu expression. The identification of five cases that expressed C mu mRNA transcripts in the absence of detectable C mu proteins also suggests that molecular techniques may be valuable in identifying a unique subgroup of pre-B-cell acute lymphoblastic leukemia cases that contain C mu mRNA transcripts, but lack C mu proteins.
authors.affiliation: Department of Pathology, University of New Mexico School of Medicine, Albuquerque.
authors.forename: J V
authors.initials: JV
authors.lastname: Little
authors.forename: K
authors.initials: K
authors.lastname: Foucar
authors.forename: M H
authors.initials: MH
authors.lastname: Duncan
authors.forename: S S
authors.initials: SS
authors.lastname: Crago
authors.forename: T S
authors.initials: TS
authors.lastname: McConnell
authors.forename: B
authors.initials: B
authors.lastname: Griffith
authors.forename: I M
authors.initials: IM
authors.lastname: Chen
authors.forename: L B
authors.initials: LB
authors.lastname: Vogler
authors.forename: C L
authors.initials: CL
authors.lastname: Willman
mesh_terms: D000293:Adolescent; D015152:Blotting, Northern; D015139:Blotting, Southern; D002648:Child; D002675:Child, Preschool; D003593:Cytoplasm / Q000737:chemistry*; D004273:DNA, Neoplasm / Q000032:analysis; D005260:Female; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D015870:Gene Expression / Q000276:immunology*; D006801:Humans; D007148:Immunoglobulin mu-Chains / Q000032:analysis* / Q000235:genetics; D016130:Immunophenotyping; D007223:Infant; D007621:Karyotyping; D008297:Male; D054198:Precursor Cell Lymphoblastic Leukemia-Lymphoma / Q000276:immunology*; D012333:RNA, Messenger / Q000032:analysis*; D012334:RNA, Neoplasm / Q000032:analysis*
chemical_list: D004273:DNA, Neoplasm; D007148:Immunoglobulin mu-Chains; D012333:RNA, Messenger; D012334:RNA, Neoplasm