title: Significance of trisomy 7 and 12 in thyroid lesions with follicular differentiation: a cytogenetic and in situ hybridization study.
abstract: In a group of benign and malignant follicular thyroid lesions, previously analyzed by conventional cytogenetics, single- and double-target fluorescence in situ hybridization studies with pericentromeric probes specific for chromosomes 7 and 12 were performed, by using isolated nuclei from paraffin-embedded specimens of: 11 goiters, 21 adenomas, 9 follicular carcinomas, and adjacent normal thyroid tissue. Nonisotopic in situ hybridization with the same probes was used in 4-microm histologic sections of four follicular carcinomas. By fluorescence in situ hybridization analysis, the percentage of goiters, adenomas, and follicular carcinomas with gains of No. 7 was 18.2%, 52.4%, and 66.0%, respectively, and with gains of No. 12 was 9.0%, 42.9%, and 66.0%, respectively. The percentage of the same lesions (goiters, adenomas, carcinomas) exhibiting polysomies of No. 7 and No. 12, as assessed by cytogenetic analysis, was 5.0% and 0.0%, 20.0% and 20.0%, and 15.8% and 10.5%, respectively. Numerical alterations of these chromosomes were not observed in normal tissue. These findings reveal that gain of chromosomes 7 and 12 is a characteristic of the morphologically altered thyroid tissue; polysomies of chromosomes 7 and 12 are more frequent in thyroid lesions than it can be detected by conventional cytogenetic studies; the increasing frequency of polysomies of chromosomes 7 and 12 from hyperplastic lesions to benign and malignant tumors seem to substantiate the existence of a multistep pathway, ie, normal thyroid --> goiter --> adenoma --> follicular carcinoma in the pathogenesis of some thyroid neoplasms.
authors.affiliation: CIPM, Portuguese Cancer Institute, and Medical Faculty of Porto.
authors.forename: L
authors.initials: L
authors.lastname: Roque
authors.forename: A
authors.initials: A
authors.lastname: Serpa
authors.forename: A
authors.initials: A
authors.lastname: Clode
authors.forename: S
authors.initials: S
authors.lastname: Castedo
authors.forename: J
authors.initials: J
authors.lastname: Soares
mesh_terms: D018263:Adenocarcinoma, Follicular / Q000235:genetics* / Q000473:pathology; D000236:Adenoma / Q000235:genetics* / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002503:Centromere / Q000235:genetics; D002881:Chromosomes, Human, Pair 12; D002897:Chromosomes, Human, Pair 7; D005260:Female; D006042:Goiter / Q000235:genetics* / Q000473:pathology; D006801:Humans; D017404:In Situ Hybridization, Fluorescence; D007621:Karyotyping; D008297:Male; D008875:Middle Aged; D013961:Thyroid Gland / Q000473:pathology; D013964:Thyroid Neoplasms / Q000235:genetics* / Q000473:pathology; D014314:Trisomy