Redefining the HPV-32 Detection Gold Standard

Contributed by Guest Blogger: R. Hendricks ’13

A recent study focuses on HPV-32, which is frequently associated with focal-epithelial-hyperplasia (FEH), which is a wart-like growth in the mucous tissues of the mouth. Detection of HPV-32 is currently labor-intensive and insensitive, so this work was focussed on testing an experimental polymerase chain reaction (PCR) assay, or measurement of the virus in a sample, to determine if it was more sensitive and user-friendly than the current gold standard method (MY09/11 amplification and dot blot hybridization).
The experimental assay was specific for the HPV-32 L1 gene, so the experimenters used samples of the HPV-32 gene from HPV-positive subjects and tested sensitivity of the current dot-blot assay by applying it to the sample and seeing how many copies of the gene it could detect and amplify. They then did the same procedure with the experimental assay, which correctly identified many more genes as HPV-32 positive. Specifically, the dot-blot assay detected HPV-32 in 24 oral samples. All but one were also identified by the HPV-32 L1 PCR, which identified an additional 78 samples. Reproducibility was also assessed, by retesting 111 samples, 57 of which were HPV-32-positive. The researchers found that 94.6% of the samples were reproducible.
The HPV-32 specific PCR system targeting the L1 gene produced significantly greater sensitivity in identifying HPV-32. It is also highly reproducible and less labor-intensive, and is therefore the new gold standard.
Follow-up experiments, such as one that targeted a different gene of HPV-32 (the E6/E7 region) were carried out to ensure that the increased sensitivity was a result of the robustness of the experimental assay. A potential next step in this research could be to target other specific genes with a similar PCR assay, to see if the robustness will remain.