Background: The synucleins (alpha, beta, and gamma) are a family of small cytoplasmic proteins that are expressed predominantly in neurons. alpha synuclein has attracted considerable attention due to its involvement in neurodegenerative diseases. Abnormal expression of gamma synuclein has recently been reported in some breast tumors. In this study, the authors examined a panel of breast and ovarian carcinomas for expression of alpha, beta, and gamma synucleins.
Methods: Normal breast and ovary tissue samples, tissue from ovaries of women at high risk of ovarian carcinoma, and tissue from breast and ovarian carcinomas were screened by immunohistochemistry and Western blot analysis for 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 simultaneously. Expression of alpha synuclein was not detected in breast carcinomas by Western blot analysis. Synuclein (alpha, beta, and gamma) expression was not detectable by immunohistochemistry in normal ovarian epithelium. Eighty-seven percent (39 of 45) of ovarian carcinomas were found to express at least 1 type of synuclein, and 42% (19 of 45) expressed all 3 synucleins (alpha, beta, and gamma) simultaneously. Highly punctate gamma synuclein expression was also observed in 20% of preneoplastic lesions of the ovary, including epithelial inclusion cysts, hyperplastic epithelium, and papillary structures, suggesting that gamma synuclein up-regulation may occur early in the development of some ovarian tumors.
Conclusions: alpha, beta, and gamma synuclein are expressed in a high percentage of ovarian and breast carcinomas, and abnormal gamma synuclein expression may occur early in the development of ovarian carcinoma.