Loss of heterozygosity in P53, BRCA1, and estrogen receptor genes and correlation to expression of p53 protein in ovarian epithelial tumors of different cell types and biological behavior

Loss of heterozygosity (LOH) of tumor suppressor genes (TSGs) in ovarian ep ithelial tumors of differing cell types and biological behavior has not bee n thoroughly investigated. Moreover, there have been conflicting reports co rrelating LOH of the p53 gene to overexpression of p53 protein. This study evaluated 34 formalin-fixed, paraffin-embedded ovarian epithelial tumors fo r LOH by polymerase chain reaction (PCR) for the following microsatellite m arkers: TP53(17p13.l/p53 gem), D17S579(17q/BRCA1 gene), and ESR (6q24-27/es trogen receptor gene). LOH of the TP53 marker was detected in 4 (44%) of 9 informative serous cystadenocarcinomas (SCa) but in 0 of 4 informative clea r cell carcinomas (CCa) and 0 of 5 informative serous tumors of low maligna nt potential (SLMP). LOH of the BRCA1 marker was detected in 5 (83%) of 6 i nformative SCa, but in 1 (13%) of 8 informative CCa and 1 (14%) of 7 inform ative SLMP. LOH of the ESR marker was detected in 4 (50%) of 8 informative SCa, but in 0 of 4 informative CCa and 1 (16%) of 6 informative SLMP. p53 p rotein overexpression was present in 8 of 12 SCa but did not correlate to T P53 LOH. LOH for TP53, D17S579/BRCA1, and ESR is common in ovarian SCa, and is observed in primary tumors as well as metastases. In contrast, these ge netic alterations are less common in CCa and in the biologically less aggre ssive SLMP tumors. These data suggest different mechanisms of oncogenesis i n ovarian epithelial tumors of different cell types and biological behavior . Copyright (C) 2000 by W.B. Saunders Company.