IMMUNOHISTOCHEMICAL ASSESSMENT OF PROLIFERATION MARKERS AND ALTERED GENE-EXPRESSION IN ARCHIVAL SPECIMENS OF OVARIAN EPITHELIAL TUMORS

Recently reported morphologic and molecular genetic evidence suggests that some ovarian carcinomas arise from their benign and low malignant potential (LMP) counterparts. In order to help reach a better underst anding of ovarian tumorigenesis, we studied a wide range of gene produ cts involved in cellular growth regulation in archival material obtain ed from three groups of tumors with graduated malignant potential. Imm unohistochemical staining was performed for Ki-67, proliferating cell nuclear antigen (PCNA), epidermal growth factor receptor (EGFR, HER-2/ neu-encoded receptor protein, p53 gene product, and multidrug resistan ce gene product (P-glycoprotein). The expression of EGFR, HER-2/neu-en codcd receptor protein, and mutant p53 product was significantly loa e r in LMP tumors than in carcinomas (p < 0.05). HER-2/neu immunopositiv ity was more prevalent in adenocarcinomas than in LMP tumors, and the proportion of HER-2/neu-positive adenocarcinomas increased with the pr ogression of the disease. The staining differences between LMP LP rumo rs and adenocarcinomas with antibodies against Ki-67, PCNA, and P-glyc oprotein were not statistically significant. Immunohistochemical detec tion of EGFR, HER-2/neu. and p53 in ovarian epithelial tumor is releva nt to ovarian tumorigenesis. It could serve as a powerful tool for the pursuit of retrospective studies focused on these important biologic markers.