Elevated expression of SOX9 is related with the progression of gastric carcinoma.

To investigate the SOX9 expression and its effects on promoting invasion and metastasis in the primary gastric adenocarcinomas. One hundred and eighty six patients with primary gastric adenocarcinomas who underwent surgery between 2002 and 2006 were classified as low, intermediate, and high SOX9 expression groups by immunohistochemistry (IHC). Our IHC performance showed that SOX9 was lowly expressed in lower crypt of the normal epithelium adjacent to the tumor, and SOX9 expression was also observed in the intestinal metaplastic epithelium, but no SOX9 expression was detected in the surface epithelium. The stronger SOX9 expression was observed in the T3-T4 group than in the T1-T2 group, and there was a significant difference between the two groups (P < 0.0005). The SOX9 expression was correlated with the lymph node metastasis, and it showed significant between N0, N1, N2, and N3 groups (P < 0.0005). Similar to the lymph node metastasis classification, the SOX9 expression was also related to the tumor staging. From the stage Ia-Ib to stage II-IIIa and stage IIIb-IV, the SOX9 expression was elevated and the difference was significant (P < 0.0005). On the contrary, the SOX9 expression was not related to the histological classification (P > 0.05). Also the SOX9 expression showed no significance in patient age (P > 0.05). The SOX9 is overexpressed in the advanced stage of gastric carcinoma. SOX9 is related to the tumor progression though promoting invasion and metastasis, probably via enhancing the adhesion between the tumor cells and matrix or vessels which facilitates the tumor cells metastasis.