HPV-related oropharyngeal squamous cell carcinomas: a comparison between three diagnostic approaches

HPV-related oropharyngeal squamous cell carcinomas clearly represent a growing entity in the head and neck with distinct carcinogenesis, clinico-pathological presentation and survival profile. We aimed to compare the HPV prevalence rates and clinico-pathological correlations obtained with three distinct commonly used HPV detection methods.

p16-immunohistochemistry (IHC), HPV DNA viral load by real-time PCR (qPCR), and HPV genotyping by a reverse hybridization-based line probe assay (INNO-LiPA) were performed on pretreatment formalin-fixed paraffin-embedded tumor samples from 46 patients treated for single primary oropharyngeal carcinomas.

Twenty-eight patients (61%) had a p16 overexpression in IHC. Twenty-nine patients (63%) harbored HPV DNA on qPCR. Thirty-four patients (74%) harbored HPV DNA on INNO-LiPA. The concordance analysis revealed a good agreement between both HPV DNA detection methods (κ=0.65); when both tests were positive, the depicted HPV subtypes were always concordant (HPV16 in 27 cases, HPV18 in 1 case). Agreement was moderate between IHC and qPCR (κ=0.59) and fair between IHC and INNO-LiPA (κ=0.22).

Certain highly sensitive methods are able to detect the mere presence of HPV without any carcinogenetic involvement while other more specific tests provide proof of viral transcriptional activity and thus evidence of clinically relevant infections. The use of a stepwise approach allows reducing false positives; p16-immunostaining seems to be an excellent screening test and in situ hybridization may overcome some of the PCR limitations.