Isothermal Method of a Recombinase Polymerase Amplification Assay for the Detection of Most Common High-Risk Human Papillomavirus Type 16 and Type 18 DNA

Background: Cervical cancer is a common gynecologic malignant tumor and has a great impact on women's health. Human papillomavirus (HPV) is implicated in cervical cancer and precancerous lesions and the two are possibly two stages of disease progression. With the technological development of molecular biology and epidemiology, detection and treatment of HPV has become an important means to prevent cervical cancer. Methods: Here we present a novel, rapid, sensitive and specific isothermal method of recombinase polymerase amplification (RPA), which is established to detect the two most common high-risk human papillomavirus type 16 and type 18 DNA. In this study, we evaluate the efficacy of the RPA assay, incubating clinical specimens of HPV16 and HPV18 using plasmids standard. It operates at constant low temperature without the thermal instrumentation for incubation. The products can be detected via agarose gel electrophoresis assay, reverse dot blot assay, and quantitative real-time assay with SYBR Green I. We assess the diagnostic performance of the RPA assay for detecting of HPV16 and HPV18 in 335 clinical samples from patients suspected of cervical cancer. Results: The results revealed no cross-reaction with other HPV genotypes and the RPA assay achieve a sensitivity of 10(0) copies. Compared with TaqMan qPCR, the RPA technique achieves exponential amplification with no need for pretreatment of sample DNA at 37 degrees C for 20 minutes, which reveals more satisfactory performance. The agreement between the RPA and qPCR assays was 97.6% (kappa = 0.89) for HPV16 positivity and 98.5% (kappa = 0.81) for HPV18 positivity, indicating very good correlation between both tests. Conclusions: Importantly, the RPA assay was demonstrated to be a useful and powerful method for detection of HPV virus, which therefore may serve as a valuable tool for rapid diagnosis of HPV infection in both commercial and clinical applications.