ALLELE LOSS FROM LARGE REGIONS OF CHROMOSOME-17 IS COMMON ONLY IN CERTAIN HISTOLOGICAL SUBTYPES OF OVARIAN CARCINOMAS

Using a panel of ten polymorphic markers, we examined the frequency of loss of heterozygosity (LOH) on chromosome 17 in 55 sporadic ovarian tumours. LOH on 17p and 17q was observed to be 50% and 62% respectivel y. LOH at D17S5 was detected in 24/36 (67%) of malignant cases and in 19/43 (44%) at TP53; the marker D17S855 intragenic to the BRCAI gene s howed allele loss in 50% (20/40) cases. The data presented here sugges t that loss of the whole chromosome 17 is a relatively frequent event (30%) in ovarian carcinomas and this observation is especially frequen t for serous, transitional cell and anaplastic histological subtypes. Mucinous and endometrioid ovarian tumours showed only short interstiti al deletions (4/11, 36%). The overall frequency of the short deletions was relatively low (7/43, 16%) in our panel of carcinomas. Amplificat ion of c-erbB-2/neu oncogene was detected in 32% (11/34) of the carcin omas tested; the gene was amplified only in those histological subtype s in which high incidence of LOH on chromosome 17 was observed, and wa s associated with advanced stages of the disease. We conclude that dif ferent histological types of tumour may have different aetiological me chanisms, and tumour-suppressor genes on chromosome 17 might be associ ated specifically with serous and transitional cell ovarian carcinomas .