OBJECTIVETo investigate the association of SOX9 expression and clinicopathologic factors and prognosis of gastric cancer.

METHODSA retrospective cohort study including 112 gastric cancer patients admitted to the Zhejiang Provincial People's Hospital from 2004 to 2006 was performed. Immunohistochemical analysis was used to evaluate the expression of SOX9 in the 112 specimens of gastric cancer tissues and 70 non-cancerous tissues adjacent to the tumor.

RESULTSLow expression of SOX9 was seen in 5(7.1%) tissues out of 70 non-cancerous tissues adjacent to the tumor. A total of 94(83.9%) patients had varying expression of SOX9, of whom 51(45.4%) had overexpression. Univariate analysis demonstrated that the expression of SOX9 was significantly associated with Lauren classification (P<0.05), tumor invasion(P<0.01), lymph node metastasis(P<0.05), distant metastasis(P<0.05) and tumor stage(P<0.05), however there was no significant association between SOX9 expression and sex, age, histological type, histology differentiation or tumor size. Kaplan-Meier analysis showed that the 5-year survival rate of patients with SOX9 over-expression was significantly lower than that of patients with low expression(29.4% vs. 49.2%, P=0.031). Multivariate Cox regression analysis showed that histology differentiation(P=0.046), tumor invasion(P=0.001), and distant metastasis(P<0.01) were independent prognostic factors for gastric cancer, however the over-expression of SOX9 was not significant(P=0.948).

CONCLUSIONSThe expression SOX9 is associated with the growth, invasion, and metastasis of gastric cancer, as well as the prognosis. However, SOX9 expression is not an independent factor for the prognosis in patients with gastric cancer.