Abstract: OBJECTIVE: To analyze the relationship between Toll-like receptor 9(TLR9) expression and clinical pathological staging in lung cancer and its impact on the results of postoperative radiotherapy in lung cancer. METHODS: The medical records of 63 patients who had received surgical treatment in our hospital in March 2007 to December 2011 were analyzed,TLR9 expression of cancer tissue was determined by SP immunohistochemistry methods. The relationship of TLR9 expression and clinical pathological staging in lung cancer was evaluated. We performed Kaplan-Meier survival analysis and multivariate Cox regression analysis on survival factors of 36 patients who received postoperative radiotherapy,and explored the significance of TLR9 expression in postoperative radiotherapy survivors. RESULTS: No TLR9 expression was found in normal pulmonary tissue,while TLR9 protein was localized in the cytoplasm of lung cancer cells. The positive rate of TLR9 protein was 68.3%(43/63). The TLR9 expression increased with the greater tumor size and lymph node metastasis of lung cancer (P<0.05). By analyzing the survival of 36 postoperative radiotherapy lung cancer patients,we found that TLR9 expression and tumor size of lung cancer significantly affected progression-free survival (PFS) and overall survival(OS) of these patients (P<0.05). Lymph node metastasis and histological type (squamous cell carcinoma or adenocarcinoma) of also affected OS and PFS of the patients (P<0.05). With Cox multivariate regression analysis,TLR9 expression,lymph node metastasis were independent prognostic factors for patient survival. CONCLUSION: Positive TLR9 expression increased in lung cancer. TLR9 expression and lymph node metastasis were independent risk factors on predicting patient survival. TLR9 could become a new molecular biological indicator to predict the survival of lung cancer patients after postoperative radiotherapy.

Key words: lung cancer, Toll-like receptor 9, postoperative radiotherapy, survival