Numerical chromosomal aberrations of chromosome 1 and 7 in dysplastic cervical smears

Cervical smears with Papanicolaou's staining (PAP) reveal only morphologica l characteristics of epithelial cells of the cervix uteri. Since chromosoma l aberrations are known to play a role in malignant transition, we analyzed cervical smears for numerical changes of the chromosomes 1 and 7 with fluo rescence in-situ hybridization to probe for a diagnostic value of these chr omosomes in the characterization of cervical dysplasia. Cervical smears wer e collected from 21 patients with suspect histology of curettage or biopsy specimen, 14 of them having been subsequently graded as cervical intraepith elial neoplasia (CIN) III and 5 as CIN II. Nineteen normal cervical smears (PAP I-II) served as controls. Smears were hybridized with chromosomal enum eration probes for chromosome 1 and 7. Disomic cells (2 copies of chromosom e 1 and 7) were decreased in the CIN II (63%) and CIN III group (57%) with respect to the control group (77%). Cells with 3 signals for chromosome 7 w ere significantly more frequent in the CIN III and the CIN II group than in the control group (6.7, 6.4 and 0.7%, respectively). Only the CIN III grou p (10%), but not CIN II (6%), showed a significant trisomy for chromosome 1 as compared with the controls (3.8%). A close correlation between the inci dence of trisomy 1 or 7 and PAP grading was observed. PAP III-IIID smears w ith high trisomy 1 counts corresponded to CIN III histology, while all CIN II patients were PAP III-IIID with low incidence of trisomy 1. We conclude that trisomy of chromosome 7 is a feature of cervical dysplasia and seems t o be an early event in dysplastic transition. In contrast, trisomy of chrom osome 1 is observed only in high grade dysplasia and may be a marker for pr e-malignant lesions. (C) 2000 Elsevier Science Inc. All rights reserved.