Evaluation of the HPV L1 Capsid Protein in Prognosis of Mild and Moderate Dysplasia of the Cervix Uteri

Cervical intraepithelial neoplasia (CIN) can be detected in the cytologic smears years before invasive squamous cancer arises, but no reproducible morphologic criteria exist to predict behavior of cervical lesions. The possibility of predicting the clinical course of cervical lesions could be of high value in clinical practice and some women will spare of unnecessary treatment. HPV L1 capsid protein represents about 90% of the total protein on the surface of the virus and can be detected in mild to moderate dysplasia and rarely in severe dysplasia. The purpose of the study was to evaluate the use of immunodetection of HPV L1 protein on archival Pap smears with findings of mild and moderate dysplasia in predicting its clinical course. Immunochemical analyses with L1 antibody revealed positively stained nuclei of squamous epithelial cells in 56 of 114 smears (49.1%). The staining results were correlated with follow-up smears or with histologic verification. Regression (negativisation of the Pap smear for 24 months or longer) was noticed in 31 of 56 (55.4%) L1-positive cases and in 20 of 58 (34.5%) L1-negative cases. Persistent disease occured in 13 (23.2%) L1-positive cases and in 14 (24.1%) L1-negative cases. Progressive disease occured in 12 (21.4%) L1-positive cases and in 24 (41.4%) L1-negative cases. The difference in the clinical course between the L1-positive and L1-negative patients was statistically significant (p =0.025). Also, the difference in the clinical course of the L1-negative staining in the under-30 and over-30 years age group was statistically significant (p=0.04). For conclusion, our data confirm that immunostaining for HPV L1 capsid protein could offer prognostic information about mild and moderate intraepithelial cervical squamous lesions.