The Relationship Between RACK1 Expression And Clinicopathologic Information Of Esophageal Squamous Cell Carcinoma

[Objective] Esophageal cancer is the eighth most common cancer and the sixth leading cause of cancer related deaths worldwide. The incidence of esophageal squamous cell carcinoma (ESCC) is more frequent in China. ESCC has a very poor prognosis, with an overall 5-year survival rate of about 25% after surgery. Yet the molecular mechanism during human esophageal squamous carcinogenesis remains unclear. In present study, we investigated the expression and relationship of Receptor for Activated C Kinase 1 (RACK1) and clinical characteristics in esophageal squamous cell carcinoma (ESCC).[Methods]Western Blot was performed to detect the RACK1 expression in ESCC cell lines. Immunohistochemistry was performed to assay the expression of RACK1 and Ki67 in 113 tumor tissues and 79 adjacent normal epithelia from ESCC patients in tissue microarray. The relationship between RACK1 level and clinicopathologic information such as age, gender, location, smoking, differentiation degree and TNM stage were analyzed.[Results] The expression of RACK1 protein was significantly down-regulated in ESCC tissues compared with the normal adjacent epithelia, the rate of strong positive expression was 69.62%(55/79) in normal epithelia, compared with 21.24%(24/113) in tumor tissues (χ2=63.363, P<0.001). Upregulated expression of RACK1 was observed in 72.5%(29/40) ESCC tissues of patients without smoking history, which was significantly higher than that in 46.6%(34/73) of patients having smoking history (χ2=7.040,P=0.008). In addition, the rate of upregulation of RACK1 was significantly higher in stage I and II group (63.8%,44/69) than that in stage III group (43.2%, 19/44) (χ2=4.616, P=0.032). Moreover, the ESCC tissues with higher Ki67 score showed lower level of RACK1 than that with lower Ki67 score (r=-0.259, P=0.006). The relationship between RACK1 expression and age, gender, tumor location, differentiation grade were not observed. The RACK1 expression was not associated with patient prognosis.[Conclusion] The expression of RACK1 was down-regulated in ESCC tissues. The expression of RACK1 was associated with smoking, TNM staging and Ki67 score of ESCC. We concluded that down-regulated RACK1 might function as tumor suppressor gene in ESCC.