Cyclin E mRNA overexpression in epithelial ovarian cancers: Inverse correlation with p53 protein accumulation

OBJECTIVE: We investigated the relationship between cyclin E mRNA overexpre ssion and p53 protein accumulation in epithelial ovarian cancers. METHODS: mRNA was isolated and cDNA was prepared from 36 epithelial ovarian tumors ( three adenomas, three low malignant potential tumors, and 30 carcinomas), a nd six normal ovaries. The cyclin E mRNA expression levels relative Co an i nternal control, beta -tubulin, were determined by semiquantitative polymer ase chain reaction (PCR). Cyclin E and p53 protein expression in ovarian ca ncer tissues were examined by immunohistochemistry using the same series of samples. Fisher exact test of significance and an unpaired t test were use d for statistical analysis. RESULTS: Considerable levels of cyclin E mRNA w ere detected in all normal ovaries and ovarian tumor samples examined by se miquantitative PCR amplification, mRNA levels of cyclin E were significantl y higher in nine of 30 (30%) ovarian cancers compared with those in normal ovalies. The immunohistochemical expression of cyclin E protein tvas confir med in the nuclei of tumor cells in 13 of 30 (43%) ovarian cancers. p53 pro tein accumulation was detected in 12 of 30 (40%) ovarian cancers examined. There was a significant inverse correlation between cyclin E mRNA over over expression and p53 protein accumulation (P <.01, Fisher exact test). CONCLU SIONS: Cyclin E mRNA overexpression frequently occurs in ovarian cancers wi thout p53 protein accumulation. Cyclin E might have an important effect on the development of a limited ntr,number of ovarian cancers. (J Soc Gynecol Investig 2001;g:179-85) Copyright <(c)> 2001 by the Society for Gynecologic investigation.