Human papillomavirus tumor-infiltrating T-regulatory lymphocytes and P53 codon 72 polymorphisms correlate with clinical staging and prognosis of oropharyngeal cancer

The association between human papillomavirus (HPV) DNA positivity, p53 codon 72 polymorphisms, and the type of leukocyte infiltration in head and neck squamous cell carcinomas (HNSCC) and their combined impact upon patient survival is poorly investigated. For this reason, leukocyte infiltration profile and p53 codon 72 polymorphisms were assessed in freshly removed HNSCC specimens (N=71 patients). HPV detection was performed by nested-PCR followed by DNA sequencing. Viral loads were determined by quantitative RT-PCR. The choice to investigate fresh instead of archive paraffin-embedded specimens was privileged to avoid possible artifacts due to sample processing. HPV DNA was detected in 14% of cases. Oropharyngeal carcinomas were the most frequently associated with the presence of HPV16 DNA (41%) and were associated with p53 Pro/Pro or Pro/Arg polymorphisms. In HPV16-positive oropharyngeal carcinomas increased infiltrations of CD3+ and FoxP3+ T-cells correlated with higher HPV16 copy numbers. The presence of HPV may trigger a stronger immune response and may be considered a reliable marker for clinical staging and a more favorable prognosis of oropharyngeal carcinoma.