EXPRESSION OF SOX9 IN ESOPHAGOGASTRIC JUNCTION ADENOCARCINOMA AND ITS CORRELATION WITH CLINICOPATHOLOGICAL CHARACTERISTICS AND PROGNOSIS

Yingcai Hong¹, Zheng Wang¹, Zhanpeng Rao¹, Jun Wan¹, Xie’an Ling¹, Zhenglei Xu^{1, 2, *}

¹Department of thoracic surgery, Shenzhen People's Hospital (the Second Clinical Medical College of Jinan University and the First Affiliated Hospital of South University of science and Technology), Shenzhen 518020, Guangdong - ²Department of Gastroenterology, Shenzhen People's Hospital (Second Clinical School of Jinan University, First Affiliated Hospital of Southern University of science and Technology), Shenzhen 518020, Guangdong

Objective: We aim to explore the expression of SOX9 in adenocarcinoma tissue at the esophagogastric junction and its correlation with clinicopathological features and prognosis. 

Methods: From January 2013 to May 2014, 114 samples of AEG tissues and 72 samples of normal paracancerous tissues at the surgical margin from the Department of Pathology at our hospital were collected. Using immunohistochemistry, we examined the esophagogastric junction adenocarcinoma (AEG) samples and compared their expression levels of human sex-determining region Y box protein 9 (SOX9) to SOX9 expression levels in adjacent cancer tissues. We further analyzed the correlation between SOX9 expression levels and clinicopathological characteristics and prognosis. 

Results: The high expression rate of SOX9 in AEG tissues was 46.49% (53/114), which was significantly higher than the low expression rate of SOX9 in adjacent tissues—8.33% (6/72). The expression of SOX9 was correlated with the Lauren classification, tumor invasion depth, lymph node metastasis, distant metastasis, and the TNM stage in patients with AEG (P<0.05). It was not related to the patients’ sex, age, tumor location, or tumor diameter tissue differentiation (P>0.05). According to Kaplan-Meier analysis, the 5-year survival rate of patients with high SOX expression was 30.19% (16/53), which was significantly lower than the 5-year survival rate of patients with low SOX expression (54.10%; 33/61). COX multivariate analysis revealed that the degree of tissue differentiation, depth of infiltration, and distant metastasis were independent risk factors affecting the prognosis of patients with AEG. 

Conclusion: SOX9 is highly expressed in AEG tissues. Its expression level is related to the occurrence, development, invasion, and metastasis of AE. While it affects the prognosis, SOX9 cannot be used as an independent risk factor for AEG patients.