Abstract: OBJECTIVE: The aim of this study was to investigate the association of Toll-like receptor 9 protein expression with cervical cancer pathogenesis. METHODS：Levels of TLR9 protein in chronic cervicitis，cervical intraepithelial neoplasia (CIN) and cervico-squamous cell carcinoma (CSCC) tissues from 97 Uighur patients were examined by immunohistochemistry. RESULTS：Immunohistochemical staining showed that TLR9 expression was mainly observed as cytoplasmic staining and was undetectable (88.2%) or weak (11.8%) in chronic cervicitis tissues，gradually increased in accordance with the histopathological grade in the following order：chronic cervicitis (2/17，11.8%)，CIN I (4/19，28.6%)，CIN II(3/10，30.0%)，CIN III(12/24，50.0%)，CSCC(17/32，53.1%). There were statistical differences among five groups (P＜0.05). The difference was statistically significant for CIN III and CSCC compared with cervicitis (P＜0.05)，but not for CIN I and CIN II (P＞0.05). CONCLUSION：This study showed that the TLR9 protein expression was，to some extent，associated with the development of cervical precancerous lesion and cancer.

Key words: TLR9, cervical squamous cell carcinoma, Uighur women, immunohistochemistry