title: Detection of translocations affecting the BCL6 locus in B cell non-Hodgkin's lymphoma by interphase fluorescence in situ hybridization.
abstract: Structural alterations in 3q27 affecting the BCL6 locus are among the most frequent changes in B-NHL. The aim of the present study was to establish an interphase-FISH assay for the detection of all diverse BCL6 translocations in B-NHL. Two different approaches were tested, one using a PAC-clone spanning the major breakpoint region (MBR) of BCL6 (span-assay), and another using two BAC clones flanking the MBR (flank-assay). Interphase FISH with the span-assay detected the various BCL6 translocations in seven B-NHL cell lines. The dual-color flank-assay was evaluated in two laboratories independently: in normal controls, the cutoff level for false-positive signals was 2.6%, whereas the cutoff level for false-negatives in the seven cell lines was 7.5%. To test the feasibility of the FISH strategies, 30 samples from patients with B-NHL with cytogenetic abnormalities of 3q27 were evaluated with both assays. In 21 cases, the span-assay indicated a BCL6 rearrangement. In 18 of the 21 cases, the dual-color flank-assay confirmed the translocation including 12 different partner chromosomal loci. The three false-positive cases detected with the span-assay showed trisomy of chromosome 3 by cytogenetic analyses, and they were correctly classified as non-rearranged with the flank-assay. In summary, our FISH strategy using two differently labeled flanking BCL6 BAC probes provides a robust, sensitive, and reproducible method for the detection of common and uncommon abnormalities of BCL6 gene in interphase nuclei. The routine application of this assay to patients with B-NHL will allow the assessment of the diagnostic and prognostic significance of BCL6 rearrangements.
authors.affiliation: Department of Hematology and Oncology, Hospital Clinico, University of Valencia, Spain.
authors.forename: D
authors.initials: D
authors.lastname: Sanchez-Izquierdo
authors.forename: R
authors.initials: R
authors.lastname: Siebert
authors.forename: L
authors.initials: L
authors.lastname: Harder
authors.forename: I
authors.initials: I
authors.lastname: Marugan
authors.forename: A
authors.initials: A
authors.lastname: Gozzetti
authors.forename: H P
authors.initials: HP
authors.lastname: Price
authors.forename: S
authors.initials: S
authors.lastname: Gesk
authors.forename: J M
authors.initials: JM
authors.lastname: Hernandez-Rivas
authors.forename: I
authors.initials: I
authors.lastname: Benet
authors.forename: F
authors.initials: F
authors.lastname: Solé
authors.forename: T
authors.initials: T
authors.lastname: Sonoki
authors.forename: M M
authors.initials: MM
authors.lastname: Le Beau
authors.forename: B
authors.initials: B
authors.lastname: Schlegelberger
authors.forename: M J
authors.initials: MJ
authors.lastname: Dyer
authors.forename: J
authors.initials: J
authors.lastname: Garcia-Conde
authors.forename: J A
authors.initials: JA
authors.lastname: Martinez-Climent
mesh_terms: D001483:Base Sequence; D002871:Chromosome Banding; D002893:Chromosomes, Human, Pair 3; D005260:Female; D015321:Gene Rearrangement; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D016393:Lymphoma, B-Cell / Q000235:genetics*; D008297:Male; D008969:Molecular Sequence Data; D014178:Translocation, Genetic