Detection and typing of human papillomavirus in cervical intraepithelial neoplasia (CIN) grade III by PCR and Dot Hybridization

Abstract

Genital human papillomavirus (HPV) is one of the most important causative agent in cervical cancer which is developed from precancerous lesion know as cervical intraepithelial neoplasia (CIN-I, CIN-II, and CIN-III). To date over 77 different HPV-types have been identified. More than 35 types are involved in anogenital diseases and 20 types or more are associated with CIN and cervical malignancy. In this study, the prevalence of HPV-infection in CIN-III and distribution of HPV-types were investigated A hundred tissue samples diagnosed as CIN-III and 100 tissues from chronic cervicitis (with a normal histologic appearance) selected as a control group were used. All specimens were formalin-fixed and paraffin embedded tissues. The extracted DNA were prepared and screened for HPV by polymerase chain reaction (PCR) using L1 consensus primers. All amplified products were analyzed by gel electrophoresis (GE) and dot hybridization (DH) using generic probe (GP), and type-specific probe (TS) specific for HPV-6,11,16,18, and 33 (TS-6, TS-11, TS-16, TS-18, and TS-33). HPV-DNA was detected in 72 % (72/100) of CIN-III 6% (6/100) of the control group, giving a crude odd ratio of 40.28 (95% CI= 19.23-84.35). Among the CIN-III group, the most prevalent was HPV-16 ; 48.61% (35/72) followed by HPV-18 ; 15.27 (11/72), HPV-6 and 33 were detected in equal percentage 5.56% (4/72) and HPV-11 was found 2.7% (2/72). Mixed infection was identified in 10 specimens i.e., HPV-6/16, HPV-16/18, HPV-16/33, and HPV-16/18/33. Twelve samples (37.5) were untyped. Our results support the hypothesis that certain HPV-types especially HPV-16 and 18 are greatly involved in the development of CIN and cervical cancer.