title: Formalin-fixed and paraffin-embedded nodal non-Hodgkin's lymphomas demonstrate the same chromosome changes as those found in frozen samples: a comparative study using interphase fluorescence in situ hybridization.
abstract: Cytogenetic studies in lymphomas classically require fresh or frozen tissue, whereas in many instances only paraffin-embedded biopsies are available. We applied an interphase FISH assay on nuclei extracted from thick paraffin sections to determine accuracy of molecular cytogenetics in such samples. Twenty-three lymphoma samples and 4 reactive lymph nodes were tested with various commercially available DNA probes, and hybridization patterns were compared with those obtained on frozen nuclei counterparts. Successful hybridization with all probes tested was observed for 23/27 (85%) paraffin-embedded tissues and for all (100%) frozen samples, and cut-off levels defining positivity were superimposable for both situations. Chromosome changes were detected in the same way, without any false-positive or false-negative cases. Hybridization signals observed on dewaxed samples were either those classically expected to define the relevant chromosome change or were atypical: all atypical changes could be demonstrated also into nuclei from the frozen counterpart. Moreover, all typical and atypical chromosome changes observed on frozen nuclei were also detected in paraffin-embedded tissues. Our study shows that our interphase FISH assay performed on paraffin-embedded samples is a valuable alternate to conventional methods to ascertain diagnosis of lymphomas as to include patients into therapeutic trials.
authors.affiliation: Hematology Laboratory, University Hospital, Angers, France. AlGodon@chu-angers.fr
authors.forename: Alban
authors.initials: A
authors.lastname: Godon
authors.forename: Franck
authors.initials: F
authors.lastname: Genevieve
authors.forename: Isabelle
authors.initials: I
authors.lastname: Valo
authors.forename: Nicolas
authors.initials: N
authors.lastname: Josselin
authors.forename: Pascaline
authors.initials: P
authors.lastname: Talmant
authors.forename: Charles
authors.initials: C
authors.lastname: Foussard
authors.forename: Herve
authors.initials: H
authors.lastname: Avet-Loiseau
authors.forename: Nobert
authors.initials: N
authors.lastname: Ifrah
authors.forename: Marc
authors.initials: M
authors.lastname: Zandecki
authors.forename: Marie-Christine
authors.initials: MC
authors.lastname: Rousselet
mesh_terms: D016477:Artifacts; D002869:Chromosome Aberrations; D004273:DNA, Neoplasm / Q000032:analysis* / Q000235:genetics / Q000302:isolation & purification; D005557:Formaldehyde; D005629:Frozen Sections; D006652:Histological Techniques / Q000379:methods; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D008198:Lymph Nodes / Q000473:pathology*; D008228:Lymphoma, Non-Hodgkin / Q000235:genetics*; D016612:Paraffin Embedding; D016707:Tissue Fixation
chemical_list: D004273:DNA, Neoplasm; D005557:Formaldehyde