HPV-related and HPV-unrelated oropharyngeal
squamous cell carcinomas are two distinct entities according to the Union for International
Cancer Control, with a better prognosis conferred to HPV-related oropharyngeal
squamous cell carcinomas. However, variable clinical outcomes are observed among patients with p16 positive
oropharyngeal squamous cell carcinoma, which is a
surrogate marker of
HPV infection. We aimed to investigate the prognostic value of
RNA CISH against E6 and E7 transcripts (HPV
RNA CISH) to predict such variability. We retrospectively included 50 histologically confirmed p16 positive oropharyngeal
squamous cell carcinomas (p16 positive immunostaining was defined by a strong staining in 70% or more of
tumor cells). HPV
RNA CISH staining was assessed semi-quantitatively to define two scores:
RNA CISH "low" and
RNA CISH "high". Negative HPV
RNA CISH cases were scored as
RNA CISH "low". This series contained 29
RNA CISH low cases (58%) and 21
RNA CISH high cases (42%). Clinical and pathologic baseline characteristics were similar between the two groups.
RNA CISH high staining was associated with a better overall survival in both univariate and multivariate analyses (p = 0.033 and p = 0.042, respectively). Other recorded parameters had no prognostic value. In conclusion, HPV
RNA CISH might be an independent prognostic marker in p16 positive oropharyngeal
squamous cell carcinomas and might help guide
therapeutics.