HER-2/neu oncogene amplification in stage I and stage III ovarian papillary serous carcinoma.

Oncogene amplification has been implicated in the genesis and progression of many cancers. Overexpression of the HER-2/neu proto-oncogene occurs in 20-30% of ovarian epithelial cancers, in which it may be of prognostic significance. Oncogene overexpression is traditionally studied using immunohistochemistry. In this study we used fluorescent in situ hybridization (FISH) to determine HER-2/neu amplification in ovarian papillary serous carcinoma and compared the frequency of amplification in two stages of the disease. Archival tissues from 23 cases of papillary serous ovarian carcinoma (9 cases of stage I and 14 cases of stage III) were analyzed by FISH using a HER-2/neu probe and a chromosome 17 centromere control probe. Determination of the level of amplification was performed according to the standard protocols of the Cytogenetics Laboratory at Rhode Island Hospital. Of the 23 cases successfully analyzed, the frequency of amplification among stage I tumors was 22% (2/9) and the frequency of amplification among stage III tumors was 71% (10/14). These results are significant (P = 0.036). The frequency of stage I tumors among amplified cases was 17% (27/12) and the frequency of stage III tumors among amplified cases was 83% (10/12). This study not only confirms the presence of a subset of ovarian papillary serous carcinoma with HER-2/neu gene amplification, but it also indicates that HER-2/neu oncogene amplification is more likely to be associated with a more advanced stage. Thus, the present data are consistent with the hypothesis that HER-2/neu amplification, similar to HER-2/neu protein over expression, is a prognostic marker of poor outcome.