Detection of DNA of human papillomavirus types 6/11 and 16/18 in cell scrapings of the uterine cervix by filter in situ hybridisation. Correlation with cytology, colposcopy and histology

Abstract

The application of filter in situ hybridisation (FISH) to detect the presence of the DNA of human papillomavirus genotypes 6/11 and/or 16/18 in cell scrapings of the uterine cervix of 248 women in Western Australia is described. The results obtained by FISH are related to cervical dysplasia as assessed by cytology, colposcopy and histology. The detection of HPV infection was more sensitive and specific by FISH than by either histological/cytological evidence of an HPV cytopathic effect (koilocytosis) or immunohistochemical staining for HPV capsid antigen using antiserum against genus specific antigen of the bovine papillomavirus. Viral DNA was detected by FISH in 65% of women with atypical cytology and of the HPV positive cases, 68% were HPV 16/18, 22% HPV 6/11 and 10% of mixed types. HPV-DNA was detected in the cervical smears of 16 women who also had HPV capsid antigen (HPV-Ag) in their cervical biopsies; HPV 6/11 was found in 4 cases and HPV 16/18 in 12 cases. The relative frequency of the HPV-Ag positive cases decreased markedly from 44% to 4% with an increase in the severity of cervical dysplasia. By comparison, the percentage of HPV-DNA positive cases remained relatively constant between 70% and 80% for all 3 categories of dysplasia. Of these, the percentage of HPV 6/11 positives decreased slightly with an increase in the severity of dysplasia as assessed by either cytology or histology, whereas the percentage of HPV 16/18 positive cases was relatively constant. HPV-DNA was found in cervical smears of 11 of 48 (23%) women who were diagnosed colposcopically to have atypical transformation zone of the cervix. In 138 women with an atypical transformation zone, 96 (70%) were found to have HPV-DNA with HPV 16/18 contributing to 83% of the HPV positive cases. All four genotypes of HPV were found to be associated with the colposcopic morphology of mosaicism (26 cases) but only HPV 16/18 was found in 12 HPV-DNA positive cases associated colposcopically with punctation and an atypical transformation zone. The detection and typing of HPV-DNA in cell scrapings by FISH is a relatively fast and non-invasive procedure which complements cytology, colposcopy and histology and should be useful in further studies of the natural history of different HPV infections and their role in cervical cancer.