To investigate the expression of fragile histidine triad(FHIT)protein and proliferating cell nuclear antigen(PCNA)protein in cervical smears, and the clinical diagnostic significance in precancerous cervical lesions.

74 cases of low-grade squamous intraepithelial lesion(LSIL)and 40 cases of high-grade squamous intraepithelial lesion(HSIL)(from June 2004 to June 2005, the Department of Obstetrics and Gynecology, First Hospital of Lanzhou University)were enrolled in this study. The expression of fragile histidine triad protein and proliferating cell nuclear antigen protein were examined in those 114 cervical tissues by immunochistochemistry.

Fragile histidine triad protein was detected in normal cervical tissue and the absence rate of fragile histidine triad in cervical intraepithelial neoplasia(CIN)and cervical cancer. The absence rate in CINⅠ,CINⅡ, CIN Ⅲ and cervical cancer tissue were 13.3%,30.0%, 60.0% and 71.4%, respectively. The expression of proliferating cell nuclear antigen protein in CIN and cervical cancer was increased and its positive expression rate in CINⅠ,CIN Ⅱ,CIN Ⅲ and cervical cancer tissue were 44.7%,60.0%, 80.0%,85.7%,respectively. Chi-square test supported the loss rate of fragile histidine triad protein and positive rate of proliferating cell nuclear antigen protein(P=0.0001)at different pathological stages with statistical significance in contrast to the control group.

The loss of fragile histidine triad protein expression occurs in the early stage of cervical carcinogenesis, which related with CIN grades. The activation of proliferating cell nuclear antigen protein is obviously higher in precancerous cervical lesions. The expression of fragile histidine triad protein and proliferating cell nuclear antigen protein can be used for assessing the malignant potential of precancerous lesions.