IDENTIFICATION OF A 1300 KILOBASE DELETION UNIT ON CHROMOSOME 7Q31.3 IN INVASIVE EPITHELIAL OVARIAN CARCINOMAS

We have used polymerase chain reaction (PCR) amplification of tandem r epeats to study the pattern of allelic loss on chromosome 7q31 in inva sive epithelial ovarian carcinomas and borderline ovarian tumors. Usin g 13 primer sets spanning loci from 7q31 to 7q32, 16 borderline and 54 invasive ovarian tumor tissue, together with their corresponding norm al tissue, were analysed. Invasive epithelial ovarian tumors demonstra ted loss of heterozygosity (LOH) at one or more loci on 7q in 32 of 54 cases (59%). The invasive epithelial ovarian tumors demonstrated the highest percentage of LOH at the loci D7S643 (20 of 40 informative cas es, 50%) and GATA44F09 (18 of 42 informative cases, 43%). In contrary, only one borderline ovarian tumor showed LOH at one locus (GATA44F09, one of 14 informative cases, 7%). Our results display a sharp contras t in the pattern of LOH between invasive and borderline ovarian tumors suggesting that allelic loss at chromosome 7q31.3 may be involved in the development and progression of invasive epithelial ovarian tumors but not borderline ovarian tumors. Further analysis of the deletion ma p for the invasive epithelial ovarian tumors showed two regions Likely to harbor ovarian tumor suppressor genes including a novel 1300 kilob ase common loss region flanked by GATA44F09 and D7S643.