Synucleins are expressed in the majority of breast and ovarian carcinomas and in preneoplastic lesions of the ovary

BACKGROUND. The synucleins (alpha, beta, and gamma) are a family of small c ytoplasmic proteins that are expressed predominantly in neurons, alpha synu clein has attracted considerable attention due to its involvement in neurod egenerative diseases. Abnormal expression of gamma nuclein has recently bee n reported hi some breast tumors. In this study, the authors examined a pan el of breast and ovarian carcinomas for expression of alpha, beta, and gamm a synucleins. METHODS. Normal breast and ovary tissue samples, tissue from ovaries of wom en at high risk of ovarian carcinoma, and tissue from breast and ovarian ca rcinomas were screened by immunohistochemistry and Western blot analysis fo r synuclein expression. RESULTS, Synucleins were not detectable by Western blot analysis in normal breast tissue. Eighty-two percent (14 of 17) of Stage III/IV breast ductal carcinomas expressed beta synuclein, gamma synuclein, or both simultaneousl y. Expression of alpha synuclein was not detected in breast carcinomas by W estern blot analysis. Synuclein (alpha, beta, and gamma) expression was not detectable by immunohistochemistry in normal ovarian epithelium. Eighty-se ven percent (39 of 45) of ovarian carcinomas were found to express at least 1 type of synuclein, and 42% (19 of 45) expressed ail 3 synucleins (alpha, beta, and gamma) simultaneously. Highly punctate gamma synuclein expressio n was also observed in 20% of preneoplastic lesions of the ovary, including epithelial inclusion cysts, hyperplastic epithelium, and papillary structu res, suggesting that gamma synuclein up-regulation may occur early in the d evelopment of some ovarian tumors. CONCLUSIONS. alpha, beta, and gamma synuclein are expressed in a high perce ntage of ovarian and breast carcinomas, and abnormal gamma synuclein expres sion may occur early in the development of ovarian carcinoma. (C) 2000 Amer ican Cancer Society.