Objective To evaluate the overexpression of cyclin G1 in cervical intraepithelial neoplasia （CIN） and cervical carcinoma

and the correlation between cyclin G1 and high-risk human papilloma virus （HPV） infection. Methods All of the specimens were obtained from the Department of Pathology of China-Japan Friendship Hospital from January 2000 to August 2004.We detected the expression of cyclin G1 with immunohistochemistry

HPV16/18 infection with in situ hybridization

and high-risk HPV infection with Hybrid capture system II （HC-II） in normal group （25 cases）

CIN I （48 cases）

CIN II （56 cases）

CIN III （54 cases）

and invasive cervical squamous-cell carcinoma （SCC

31 cases）. Results The positive rates of cyclin G1 expression in CIN（77.85%）and SCC cervical tissues （87.10%） were significantly higher than normal （8.00%

P<0.01）

and the intensities of cyclin G1 expression in CIN（40.60%）and SCC cervical tissues （61.51%） were significantly higher than normal （2.72%

P<0.05）. The positive rates and intensities of cyclin G1 expression increased gradually with the grade of cervical lesions. High-risk HPV infection rates were higher in CIN and SCC than normal groups （P<0.05）. There was a positive correlation between cyclin G1 expression and high-risk HPV infection detected with HC-II （Kendall’s tau-b=0.316

0.269

0.352

and 0.474 in CIN I

CINII

CIN III

and SCC

respectively

P<0.05）. Conclusions Cyclin G1 is overexpressed in CIN and SCC. Cyclin G1 may be a biomarker for detecting CIN and SCC. Cyclin G1 may play an important role in the oncogenesis of CIN and SCC by high-risk HPV infection.