Histological and cytological evidence of viral infection and human papillomavirus type 16 DNA sequences in cervical intraepithelial neoplasia and normal tissue in the west of Scotland: evaluation of treatment policy

Abstract

Biopsy samples from 27 patients referred to a colposcopy clinic in Glasgow for cervical abnormalities were assessed for the relations among colposcopic appearances, cytological and histological diagnosis, expression of papillomavirus antigen, and the presence of human papillomavirus (HPV) types 6, 11, 16, and 18 deoxyribonucleic acid (DNA) sequences. Specimens were from colposcopically abnormal areas of the transformation zone and from colposcopically apparently normal areas of the zone in the same patients (paired matched internal control tissue). All 27 women referred for abnormal smears had colposcopic abnormalities. HPV-16 or 18 DNA sequences were detected in 20 of the 27 colposcopically abnormal biopsy samples and 13 of the 27 paired normal samples. Twelve samples of colposcopically normal tissue contained histological evidence of viral infection but only four of these contained HPV DNA sequences. The other nine samples of colposcopically normal tissue which contained HPV DNA sequences were, however, histologically apparently normal. HPV-6 and 11 were not detected. Integration of the HPV-16 genome into the host chromosome was indicated in both cervical intraepithelial neoplasia and control tissues. In two thirds of the HPV DNA positive samples the histological grade was classed as normal, viral atypia, or cervical intraepithelial neoplasia grade 1. Papillomavirus antigen was detected in only six of the abnormal and three of the normal biopsy samples, and HPV DNA was detected in all of these. The detection of HPV DNA correlates well with a combination of histological and cytological evidence of viral infection (20 of 22 cases in this series). A poor correlation between the site on the cervix of histologically confirmed colposcopic abnormality and the presence of HPV DNA sequences implies that a cofactor other than HPV is required for preneoplastic disease to develop. A separate study in two further sets of biopsy samples examined the state of HPV DNA alone. The sets were (a) 43 samples from cervical intraepithelial neoplasia and nine external controls and (b) 155 samples from cervical intraepithelial neoplasia, cervical cancer, vulval intraepithelial neoplasia, and vulval cancer and external controls. HPV-11 was found in only two (4·7%) of the 43 specimens from cervical intraepithelial neoplasia, whereas HPV-16 was found in 90 (58%) of the other 155 specimens. These results also suggest that HPV subtype is subject to geographical location rather than being an indicator of severity of the lesion or of prognosis.