EARLY INVOLVEMENT OF 6Q IN SURFACE EPITHELIAL OVARIAN-TUMORS

Complex karyotypes are often seen in primary surface epithelial ovaria n tumors (SEOTs). Conventional cytogenetic as well as fluorescence in situ hybridization analyses coupled with loss of heterozygosity studie s identified abnormalities of chromosome 6 as one of the most frequent lesions in these types of tumors. We performed cytogenetic analysis o f direct preparations from 40 SEOTs, including borderline tumors and l ow-, intermediate-, and high-grade carcinomas to verify the frequency of chromosome 6 alterations. We also carried out fluorescence in situ hybridization analysis with a chromosome 6 library and yeast artificia l chromosome clones from a region of the same chromosome (6q27). Chrom osome 6 abnormalities were identified in 30 of 32 analyzable SEOTs. Tw enty-five of 32 cases showed a deletion of 6q irrespective of their hi stological grade. We wish to underline that this is the first report p roving that del(6q) was the most frequent chromosome anomaly in near-d iploid SEOTs and that it was the sole anomaly observed in four SEOTs w ith diploid complement. Our findings suggest that abnormalities of the telomeric region of chromosome 6 (6q27) may be considered one of the earliest lesions in the pathogenesis of ovarian carcinomas.