In situ hybridization study on the localization of HPV DNA in the precancerous lesions of uterine cervix

Human papillomavirus (HPV) types 16 and 18 have been found closely associated with cervical cancer. In order to investigate the relationship between HPV DNA and cervical precancerous lesions, we examined the formalin fixed specimens obtained from 22 cases of mild dysplasia, 33 cases of moderate dysplasia and 31 cases of severe dysplasia of the uterine cervix for the presence of HPV 6/11, 16 and 18 DNAs by in situ hybridization using the biotinylated HPV DNA probes. We also followed some HPV DNA positive cases of cervical dysplasia for more than 6 months prospectively. The results of in situ hybridization analysis revealed that HPV DNA was detected in the nuclei of koilocytosis, dysplastic cells and metaplastic cells. HPV 6/11 was positive in 27.3% (6/22) of mild dysplasia and 21.2% (7/33) of moderate dysplasia. On the other hand, HPV 16 positive rate increased with the grade of dysplasia and 36.4% (12/33) of moderate dysplasia, 61.3% (19/31) of severe dysplasia were positive for HPV 16 DNA. Some of the follow-up cases which were positive for HPV 16 DNA were later found to have carcinoma in situ. Our results suggest that HPV type 16 might play an important role in cervical carcinogenesis.