Abstract: Objective：To explore the expressssion of mitogen-activated extracellular signal-regulated kinase（MEK） signaling pathways in cervical precancerous lesions and cervical cancer. Methods: A total of 92 patients with cervical lesions were collected between January 2013 and April 2014 in the department of gynecology of Tianjin First Central Hospital. According to the degree of cervical lesions, the patients were divided into three groups: normal group（30 cases）, high level cervical intraepithelial neoplasia（CIN） group（30 cases）, cervical cancer group（32 cases）. Using immunohistochemical SP method to detect the MEK expression in different tissues. Results: In normal group, high level CIN group and cervical cancer group, the positive rates of MEK were 20.0%，56.7%，68.8% respectively. MEK positive expression rate is highest in the cervical cancer group, higher than that of the high level CIN group and normal group（P＜0.05）. The difference between the normal group and the high level CIN group was the statistical significant（P=0.003）. MEK positive expression rate had no correlated with patients′ age, cervical cancer pathological type, degree of tumor differentiation, tumor size and clinical stage（P＞0.05）. Conclusions: MEK pathway may play a certain role in cervical cancer and precancerous lesion development.

Key words: Uterine cervical neoplasms, Precancerous conditions, Mitogen-activated protein kinases, Signal transduction, Uterine cervical neoplasms, Precancerous conditions, Mitogen-activated protein kinases, Signal transduction