The testing strategy for detection of biologically relevant infection of human papillomavirus in head and neck tumors for routine pathological analysis
Abstract
There is a subgroup among head and neck squamous cell carcinomas, which is etiologically linked to the infection of high-risk human papillomavirus (HPV). In recent studies, HPV related squamous cell carcinomas have been placed in a separate group because of their different epidemiology, distinctive histopathological characteristics, therapeutic response and clinical outcome.
The reported prevalence of high-risk HPV in head and neck tumors varies in different studies. This fact occurs mainly due to the absence of a widely accepted consensus for HPV detection in head and neck malignancies.
We present a methodological algorithm for detection of biologically relevant HPV infection: a combination of an immunohistochemical staining of the p16 protein – a surrogate marker for a transforming HPV infection, and a molecular genetic identification of HPV DNA by three different polymerase chain reactions (PCR). The study group consisted of 41 patients with a tumor in head and neck region.
A verification of detection of biologically relevant HPV infection has been performed in 10 available samples using an alternative approach, which comprised the detection of RNA transcript of HPV by reverse transcription followed by PCR (RT-PCR), and further in situ hybridization (ISH) with a commercial high-risk HPV probe. We have found a high correlation between HPV DNA detection using triple-PCR approach and strong diffuse positivity of the p16 protein (correlation coefficient 0.94) and have confirmed the validity of this algorithm.
In 94 % of HPV related squamous cell carcinomas HPV type 16 was detected. In one case HPV type 33 was identified.
That is in agreement with earlier published data. A more appropriate alternative method for the detection of biologically relevant- transforming HPV infection seems to be RT-PCR, which proved 100 % agreement with the original methodological approach of p16 determination and PCR status.