Development and validation of real-time recombinase polymerase amplification-based assays for detecting HPV16 and HPV18 DNA

ABSTRACT Cervical cancer is the fourth leading cause of cancer-related death among women worldwide. Persistent human papillomavirus (HPV) infection is the principal cause of cervical cancer, with HPV16 and HPV18 accounting for about 70% of cases worldwide. Cervical screening is an effective secondary measure for preventing cervical cancer. Testing for HPV DNA is becoming increasingly important in cervical cancer screening. The existing PCR-based HPV detection technology has several disadvantages: the assays are time-consuming, and sophisticated equipment is required to control the temperature cycles. These drawbacks have led to the development of detection technologies based on isothermal amplification. Here, we present real-time recombinase polymerase amplification (RPA-exo)-based assays for single genotyping of either the E7 or the L1 segment of HPV16 or HPV18. These assays were highly sensitive, able to detect HPV in all clinical samples with Ct values below 34, and yielded results within 25 min. A dual-detection system capable of detecting both HPV16 and HPV18 in a single reaction was also developed based on the L1 gene. It has a limit of detection of approximately 10,000 copies of each genotype per reaction. The assays were validated with DNA extracted from 36 biopsy specimens and 42 exfoliated cell samples from 43 patients with cervical lesions at different stages. The RPA-exo system is a promising clinical detection platform with the advantages of yielding results rapidly and operating at a constant temperature, while being cost-effective and easy to use. IMPORTANCE HPV DNA screening is an effective approach for the prevention of cervical cancer. The novel real-time recombinase polymerase amplification-based HPV detection systems we developed constitute an improvement over the HPV detection methods currently used in clinical practice and should help to extend cervical cancer screening in the future, particularly in point-of-care test settings.