Diagnosis of HPV-driven head and neck cancer with a single test in routine clinical practice.

Accurate screening of HPV-driven head and neck squamous cell carcinoma is a critical issue. Although there are commercial direct and indirect assays for HPV-related head and neck squamous cell carcinoma, none are ideal. Recently, a novel RNA in situ hybridization test (the RNAscope HPV-test) has been developed for the detection of high-risk HPV E6/E7 mRNA in formalin-fixed paraffin-embedded tissue. However, validation of this assay against the 'gold standard' (identification of high-risk HPV E6/E7 mRNA in fresh-frozen tissue by quantitative real-time (qRT)-PCR) has only been reported by one team. Formalin-fixed paraffin-embedded samples from 50 patients with tonsil or tongue base carcinoma were tested using the RNAscope HPV-test, p16 immunohistochemistry, and chromogenic in situ hybridization for high-risk HPV-DNA. The results were compared with those of qRT-PCR on matched fresh-frozen samples. Compared with the reference test, the sensitivity, specificity, positive, and negative predictive values of the RNAscope HPV-test and of p16 immunohistochemistry were 93%, 94%, 96%, 88% and 96%, 93%, 96%, and 93%, respectively. Five cases were discrepant between the RNAscope HPV-test and p16-immunohistochemisrty. The RNAscope HPV-test demonstrated excellent analytical performance against the 'gold standard' and is easier to interpret than chromogenic in situ hybridization. p16-immunohistochemistry also performed very well, however its main weakness is that it is an indirect marker of the presence of HPV. These data suggest that the RNAscope HPV-test is a promising test that could be developed as a clinical standard for the precise identification of HPV-driven oropharyngeal squamous cell carcinoma.