Synuclein-gamma predicts poor clinical outcome in esophageal cancer patients

The synuclein gamma (SNCG) protein, a member of neuronal protein family synuclein, has been considered as a promising potential biomarker as an indicator of cancer stage and survival in patients with cancer. The present study was conducted to evaluate the prognostic value of SNCG in patients with esophageal carcinoma (EC). SNCG levels were assessed immunohistochemically in cancer tissues from 73 EC patients. Median age was 57 (range, 29-78) years old. Forty-seven percent of the patients were male. Thirty-seven percent of the patients had upper or middle localized tumor whereas 59 % had epidermoid carcinoma. More than half of the patients (61 %) had undergone operation where 57 % received adjuvant treatment including chemotherapy or chemotherapy plus radiotherapy. Median overall survival was 11.3 ± 1.8 months (95% confidence interval (CI): 7.7-14.9 months). SNCG positivity was significantly associated with the histological type of EC and inoperability (for SNCG positive vs. negative group; epidermoid 80 vs. 53 %; p = 0.05 and inoperable 59 vs.32 %; p = 0.04, respectively). Lymph node metastasis, inoperability and receiving no adjuvant treatment had significantly adverse effect on survival in the univariate analysis (p = 0.01, p < 0.001, and p = 0.001, respectively). SNCG positivity had significantly adverse effect on survival in both univariate and multivariate analysis (p = 0.02 and p = 0.01, respectively). Our results are the first to suggest that SNCG is a new independent predictor for poor prognosis in EC patients in the literature.