Loss of heterozygosity on chromosome 17q in epithelial ovarian tumors: association with carcinomas with serous differentiation.

Loss of heterozygosity (LOH) on chromosome 17q is frequent in epithelial ovarian tumors, but its clinicopathologic significance remains to be elucidated. DNA of 50 patients with epithelial ovarian tumors was extracted from blood and from fresh-frozen and paraffin-embedded tissue (14 benign, 7 borderline, and 29 malignant). Six microsatellite loci were amplified by PCR (D17S250, TRHA1, D17S800, D17S855, D17S579, D17S513). LOH was scored by the absence or reduction of the signal to less than 50% of one of the alleles in tumor DNA compared with normal DNA. LOH was identified on chromosome 17q in at least one locus in 12 tumors (24%), all of them carcinomas (12 of 29 tumors, 41.3%). It occurred more frequently among high-grade serous carcinomas (8 of 14 tumors, 57%) and mixed endometrioid-serous carcinomas (2 of 5, 40%). LOH was detected in all informative markers of 10 tumors, suggesting the complete loss of an entire chromosome 17 homologue. Patients with LOH-positive carcinomas were older than those with LOH-negative malignant tumors (mean ages 67 and 49). The results support the hypothesis that LOH on chromosome 17q may be associated with the development of ovarian cancers in elderly patients, particularly with high-grade serous or mixed endometrioid-serous carcinomas.