Current human papillomavirus (HPV) detection methods in oropharyngeal
squamous cell carcinoma (OPSCC) have varying sensitivity and
specificity. We aimed to compare different HPV-detection methods against
the test used in clinical practice, ie, p16 immunohistochemistry (IHC)
and to evaluate whether another HPV-detection test additional to p16 IHC
would be worthwhile in OPSCC specimens. The study cohort comprised 357
consecutive OPSCC patients during two time periods: 2000-2009 and
2012-2016. From tumor tissue slides, HPV mRNA via in situ hybridization
(ISH), HPV DNA via ISH and HPV DNA via polymerase chain reaction (PCR)
were detected. The results of these methods were compared with p16 IHC
results. Additionally, clinicopathological factors were compared with
the methods studied. The sensitivity of HPV mRNA ISH, HPV DNA ISH and
HPV DNA PCR were 93.4%, 86.3%, and 83.5%, respectively. The
corresponding specificity was 92.4%, 95.3%, and 89.1%, respectively. The
negative predictive value for p16 IHC was highest (89.0%) when using
mRNA ISH, and followed by DNA ISH (83.5%). ISH for high-risk HPV E6/E7
mRNA was found to be a highly specific and sensitive method for
detecting HPV in OPSCC. As p16 protein may be overexpressed due to
HPV-independent mechanisms, all p16 IHC–positive OPSCCs should be
considered for retesting using mRNA ISH in order to verify
transcriptionally active HPV. This is especially critical when
considering de-escalated treatment approaches for patients with
HPV-positive tumors and still maintaining favorable outcomes for this
subgroup of patients.