HPV-16 E6 L83V variant in squamous cell carcinomas of the upper aerodigestive tract

The aim of this prospective case series study was to determine the prevalence of HPV-DNA, analyze the E6 mRNA expression, identify intra-type variation in the E6 oncogene in upper aerodigestive tract (UADT) squamous cell carcinoma (SCC), and correlate the presence of HPV-DNA with several clinical parameters and outcome. Frozen samples of UADT-SCC were analyzed for the presence and characterization of HPV-DNA and RNA sequences by means of polymerase chain reaction (PCR), reverse transcriptase-PCR, and direct sequencing of amplified products. HPV-DNA sequences were detected in 10% of the tumors, all of which were typed as HPV-16. Positivity for HPV-16 E6/E7 mRNA was observed in five of the eight HPV-positive tumors (62.5%). The HPV-16 E6 L83V variant was present in five cases. Multivariate analysis identified a history of absence of smoking (P = 0.009) as a predictor of HPV-positive tumor. No significant differences in overall and disease free survival curves were observed between patients with HPV-positive tumors and patients with tumors without detectable HPV-DNA. Our findings support the etiological participation of HPV-16 in a subset of UADT-SCCs from patients lacking traditional risk factors. The potential prognostic significance of HPV-16 E6 L83V variant in HPV-16 positive UADT-SCCs should be more extensively investigated.