ABSTRACT
Epithelial ovarian cancer probably occurs due to activation of several different combinations of genes, which produce cancers that vary biologically and clinically. We tested this hypothesis in 100 consecutive ovarian carcinomas by molecular biology techniques at the DNA and protein levels in three genes (erbB-2, myc, ras), which are frequently altered in this tumor system. Abnormally high expression of erbB-2 gene encoded p185 protein was observed in 31% of the samples, while erbB-2 gene amplification was detected by Southern analysis in 8%. ErbB-2 abnormal gene expression did not significantly affect the clinical outcome of patients, conferring a marginal worsening of survival. In 25 out of 96 (26%) tumor samples there was myc amplification. Higher levels of the ras-encoded p21 protein than in normal ovaries and benign ovarian tumors were found in 45% of the samples. Simultaneous overexpression of p185 and p21 was associated with shorter disease free (p = 0.02) and overall survival (p = 0.04) at significance levels notably higher than those observed for these oncoproteins singly. In addition, survival of patients with myc amplification and high p185/p21 coexpression was significantly worse (p < 0.05) than that of patients with normal levels. Our data suggest that concurrent abnormal gene expression may act synergistically to endow ovarian tumor cells with a highly aggressive phenotype. Evaluation of these genes may be helpful in the biological characterization of ovarian cancer and in defining individual patient prognosis.
