Detection of human Papillomavirus 18 in cervical cancer samples using PCR-ELISA (DIAPOPS)

BACKGROUND AND OBJECTIVES: Human Papillomavirus (HPV) infection is a major risk factor for adenocarcinoma of the cervix. The high-risk types of the virus such as HPV16 and HPV18, which possess the E6 and E7 oncogenes, are responsible for approximately 50% of all cervical cancers. A rapid, sensitive and specific test has been proposed for detection of HPV to improve cervical cancer screening programs. OBJECTIVES: The aim of this study was to develop a fast PCR-ELISA assay designated as DIAPOPS (Detection of Immobilized Amplified Products in a One Phase System)for detection of HPV16 and HPV18 types in SCC samples and Pap smears. The type specific primers and probes were designed for PCR and PCR-ELISA. The amplified products were hybridized with a specific biotin-labeled probe for HPV18 inner amplicons. The hybrids were detected with peroxidase conjugated avidin. The test was performed on the paraffin block and Pap smear samples from the cervical cancer patients, and the results of DIAPOPS were compared with conventional PCR assay. RESULTS: The 70 samples (SCC and Pap smear samples) were collected from Imam Khomeini and Mirzakoochak Khan Hospitals in Tehran. The PCR-based method detected six HPV16 positive, three HPV18 positive and Two HPV33 positive samples. DIAPOPS results were compared with the conventional PCR results and they showed an increase in sensitivity of the DIAPOPS test. Not only all of them were confirmed by PCR-ELISA but also three samples that conventional PCR showed negative for HPV18, were demonstrated positive by the PCR-ELISA method. CONCLUSION: The results of the study show that modified PCR-ELISA assay is more sensitive to detect HPV types and can be used for diagnostic purposes.