Association of Toll like receptor 9 expression with lymph node metastasis in human breast cancer

The toll like receptor 9(TLR9) has been suggested to play an important role in the invasion and metastasis of cancer cells in vitro. However, the expression of TLR9 in human cancer specimens has never been characterized. In this study, we investigated the expression of TLR9 in breast cancer specimens and determined the association between its expression and the clinicopathological features observed. We found that TLR9 expression was significantly higher in patients with breast cancers displaying large tumor size (P = 0.040), lymph node metastasis (P < 0.001) or advanced pathological stage (P = 0.006). TLR9 expression was also increased in ER negative breast cancer specimens (P = 0.043). Logistic regression analysis revealed that pathological stage (P = 0.007) and TRL9 (P = 0.001) expression were independent factors that influenced axillary lymph node metastasis of breast cancer. Patients with positive TLR9 expression had a higher progress free survival compared with the TLR9-negative cohort (P = 0.037). Therefore we concluded that Lymph node metastasis more likely occur in breast cancer patients with a positive TLR9 status and its expression might serve as an indicator of poor prognosis in patients with breast cancer.