Synuclein gamma predicts poor clinical outcome in colon cancer with normal levels of carcinoembryonic antigen

Synuclein gamma (SNCG), initially identified as a breast cancer specific gene, is aberrantly expressed in many different malignant tumors but rarely expressed in matched nonneoplastic adjacent tissues. In this study, we investigated the prognostic potential of SNCG in colon cancer particularly in the patients with normal carcinoembryonic antigen (CEA) levels. SNCG levels were assessed immunohistochemically in cancer tissues from 229 colon adenocarcinoma patients with a mean follow-up of 44 months. Correlations between SNCG levels and clinicopathologic features, preoperative serum CEA level, and clinical outcome were analyzed statistically using SPSS. SNCG levels in colon adenocarcinoma were closely associated with intravascular embolus and tumor recurrence but independent of preoperative serum CEA levels. SNCG expression was an independent prognostic factor of a shorter disease-free survival (DFS) and overall survival (OS) (P < 0.0001). Multivariate analysis revealed that both tissue SNCG and serum CEA were independent prognostic factors of DFS (P = 0.001,