Abstract: Objective To investigate the expression and significance of syntaxin 8 (STX8) in non- small cell lung cancer (NSCLC), and analyze the relationship between STX8 expression and clinicopathological features of NSCLC.Methods Seventy samples of NSCLC and 70 samples of pericancerous tissues were collected for immunohistochemistry staining, and another 10 samples of NSCLC and pericancerous tissues were used for RNA and protein extraction. qRT-PCR was performed to detect the expression of STX8 mRNA, and Western blot assay was adopted to detect the expression of STX8 protein. The relationship between STX8 expression and clinicopathological features of NSCLC was analyzed. Results Results of qRT-PCR showed that the expression of STX8 mRNA was significantly higher in NSCLC tissues than that in the pericancerous tissues (3.962 5±0. 487 3 vs. 0.538 2±0.097 5, t=21.797, P<0.01). Immunohistochemistry results showed that the high expression rate of STX8 was significantly higher in NSCLC tissues than that in the pericancerous tissues [71.43%(50/70) vs. 38.57% (27/70), χ2=15.267, P<0.01]. Western blot results showed that the expression of STX8 protein was significantly higher in NSCLC tissues than that in the pericancerous tissues (2.496 1±0.362 5 vs. 0.340 2±0.119 1, t=17.876,P<0.01). The high expression rate of STX8 was significantly different in different histological types of NSCLC (P <0.05). The high expression rate of STX8 was higher in squamous cell carcinoma and adenocarcinoma than that in adenosquamous carcinoma, and the high expression rate of STX8 was not observed in large cell carcinoma. There were no significant differences in expressions of STX8 in NSCLC patients with different gender, ages, tumor diameters, TNM stages and with or without lymph node metastasis (P>0.05). Conclusion A high expression of STX8 in NSCLC tissues may be correlated with the occurrence and development of NSCLC.

Key words: carcinoma, non-small-cell lung, SNARE proteins, syntaxin 8