Loss of heterozygosity atBRCA1/2 loci in breast and ovarian tumors is a suggested risk factor for germlineBRCA1/2 mutation status. We evaluated the presence of losses of selected microsatellite markers localized on chromosomes 17 and 13q in hereditary and sporadic ovarian tumors. 151 consecutive primary ovarian tumors (including 21 withBRCA1/2 mutations and 130 without the mutations) were screened for loss of heterozygosity at loci on chromosomes 17 and 13q. Losses of heterozygosity of at least one microsatellite marker localized on chromosomes 17 and 13q were revealed in 123 (81.5%) and 104 (68.9%) tumors, respectively. Losses of all informative markers on chromosomes 17 and 13 occurred in 30 (19.9%) and 31 (20.5%) tumors, respectively. There was no difference in the frequency of losses atBRCA1 intragenic markers (D17S855 and D17S1323) between BRCA1-positive and BRCA1-negative patients. The frequency of losses on chromosome 17 was higher in high-grade than in low-grade carcinomas. Loss of heterozygosity on chromosomes 17 and 13q is a frequent phenomenon in both hereditary and sporadic ovarian cancers. The frequency of losses atBRCA1 intragenic markers in the ovarian tumor tissue is not strongly related to the presence ofBRCA1 germline mutations.

中文翻译：

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遗传性和散发性卵巢癌中 BRCA1/2 位点的杂合性缺失。

乳腺和卵巢肿瘤中BRCA1/2位点杂合性的丧失是种系BRCA1/2突变状态的建议风险因素。我们评估了遗传性和散发性卵巢肿瘤中位于染色体 17 和 13q 上的选定微卫星标记丢失的存在。151 例连续原发性卵巢肿瘤（包括 21 例BRCA1/2在染色体 17 和 13q 上的基因座上筛选了 130 个突变和 130 个没有突变的基因的杂合性缺失。分别在 123 (81.5%) 和 104 (68.9%) 个肿瘤中发现至少一种位于染色体 17 和 13q 上的微卫星标记的杂合性丢失。染色体 17 和 13 上所有信息标记的丢失分别发生在 30 (19.9%) 和 31 (20.5%) 个肿瘤中。有是在损失的发生频率没有区别BRCA1 BRCA1阳性和BRCA1阴性患者之间的基因内标记（D17S855和D17S1323）。高级别癌中 17 号染色体丢失的频率高于低级别癌。17 号和 13q 号染色体杂合性缺失是遗传性和散发性卵巢癌的常见现象。BRCA1的损失频率卵巢肿瘤组织中的基因内标志物与BRCA1种系突变的存在没有强相关性。