Objective: Human Papilloma Virus (HPV) infection is well-established as a cause of cervical cancer. Importantly, early HPV detection can decrease both the frequency and mortality of HPV-related cancers. In situ hybridization (ISH) is a widely used method for the early detection of HPV. Yet, ISH can be expensive, time-consuming and, in some cases, insufficiently sensitive to detect nucleic acid target at low copy number, which may lead to false-positive or false-negative results. To address these limitations, we recently developed a novel in situ hybridization technology based on proprietary Loop RNA probes (LRPs)^, which provides enhanced sensitivity, high-specificity and improved cost-effectiveness.

Patients and Methods: Manual and automated ISH was performed on paraffin-embedded cervical cancer cell lines and cervical biopsy tissues obtained from HPV-positive and -negative patients. ISH was also performed on liquid-based cytology samples, spread in monolayer, for the detection of HPV in cervicovaginal samples.

Results: We compared our Loop RNA probes and reagents with commercially available kits for detecting HPV. LRPs were able to detect a single copy genome- integrated HPV, as well as HPV RNA in cell lines, patient biopsies and in liquid-based cytology samples.

Conclusions: Our results show that LRP technology is a powerful system for the in-situ detection of HPV DNA and RNA at low copy number, even down to a single copy of genome-integrated HPV.