Genetic imbalance on chromosome 17 in papillary serous carcinoma of the peritoneum.

We extend the evaluation of allelic loss patterns on chromosome 17 to papillary serous carcinoma of the peritoneum (PSCP) which is histologically identical to papillary serous ovarian carcinoma (PSOC). DNA was obtained from 11 archival cases of PSCP, with 1-11 tumor sites per case. Using ten loci spanning chromosome 17, loss of heterozygosity (LOH) was identified in all 11 cases (100%). Furthermore, 75-100% of informative cases exhibited LOH at the loci p53, D17S1322 (intragenic to the tumor suppressor gene BRCA1), D17S1327 and MPO. PSCP cases exhibit a higher rate of LOH at most loci when compared with PSOC. Alternating allelic loss at different tumor sites was identified in three cases supporting a multifocal origin of PSCP. Microsatellite instability (MI) is an uncommon event which was identified in four cases. These data implicate chromosome 17 as a potential location of genetic events important in the pathogenesis of PSCP as well as ovarian cancer.