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

BACKGROUND The synucleins (α, β, and γ) are a family of small cytoplasmic proteins that are expressed predominantly in neurons. α synuclein has attracted considerable attention due to its involvement in neurodegenerative diseases. Abnormal expression of γ 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 α, β, and γ 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 β synuclein, γ synuclein, or both simultaneously. Expression of α synuclein was not detected in breast carcinomas by Western blot analysis. Synuclein (α, β, and γ) 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 (α, β, and γ) simultaneously. Highly punctate γ synuclein expression was also observed in 20% of preneoplastic lesions of the ovary, including epithelial inclusion cysts, hyperplastic epithelium, and papillary structures, suggesting that γ synuclein up‐regulation may occur early in the development of some ovarian tumors. CONCLUSIONS α, β, and γ synuclein are expressed in a high percentage of ovarian and breast carcinomas, and abnormal γ synuclein expression may occur early in the development of ovarian carcinoma. Cancer 2000;88:2154–63. © 2000 American Cancer Society. α, β, and γ synuclein are expressed in a high percentage of ovarian and breast carcinomas, and abnormal γ synuclein expression may be a biomarker of impending ovarian carcinoma.