Detection of Human Papillomavirus Type 16 in Invasive Cervical Cancer by Polymerase Chain Reaction

Abstract

Human papillomaviruses (HPV) have been implicated as etiologic agents in the genesis of cervical carcinoma and certain other benign lesions of the cervix. Clinical and epidemiological data, and the demonstration of HPV 16 viral DNA sequences in cervical cancer biopsies lend support to the etiologic association of HPV type 16 and cervical carcinoma. Interpretation of the association between HPV 16 and cervical cancer is limited by methods of detection. Different methods of detection of viral DNA sequences have been used based on DNA-DNA hybridization. Recently, a method based upon the in vitro enzymatic amplification of specific viral DNA sequences or polymerase chain reaction (PCR) has been used. The purpose of this study was to compare PCR with DNA-DNA hybridization methods in clinical specimens obtained from invasive cervical cancer. The in vitro enzymatic amplification or PCR was carried out on three specific regions of HPV 16. E6, E7 and L1 regions of HPV 16 were chosen as the target sequences of amplification and primers were synthesized specific to these regions. PCR was performed on 163 cervical cancer specimens using primers specific for E6 and E7 regions of HPV 16. 112 of these specimens were also analyzed using L1 primers of HPV 16. Estimates of sensitivity and specificity of the different methods to see if PCR is a better, more sensitive method compared to the other methods were computed. The results suggest that although percent positivity by PCR method increases significantly, thereby improving sensitivity of detection, the specificity suffers compared to the other methods. However the advantages of using PCR as a diagnostic tool are attractive, as it requires only picogram quantities of DNA, is rapid and easy to perform, and is amenable to automation.