Methods: 140 SCC from selected intra oral sites were used (tongue, floor of mouth, buccal mucosa, gum and alveolus (ICD10, CO2-CO4). Lesions from oropharyngeal sites including base of tongue and palate were excluded (CO1, CO9-CO14). DNA was extracted from paraffin sections (Qiagen mini-kit) and analysed for HPV using GP5+/GP6+ and SPF1/SPF2 consensus primers. All positives and selected negatives were further analysed by in-situ hybridisation using a wide spectrum HPV probe (Dako). Positives were also sequenced to determine HPV type. Positive controls were 8 HIV-associated warts previously PCR positive, and 8 papillomas positive by immunocytochemistry. Negative controls were 20 fibro-epithelial polyps (FEP).
Results: Two lesions (1.4%) were positive for HPV DNA, by PCR and in-situ hybridisation. 17 selected PCR negative cases were also negative by in-situ hybridisation. Both positive cases were HPV-16. All positive controls were positive and FEPs were negative. Both positive cases were conventional invasive SCC with moderate differentiation. All verrucous or papillary cases were negative and there was no correlation to invasive pattern.
Conclusions: The results support the current literature and further confirm that HPV infection is rare in intra-oral carcinomas. HPV probably does not have an important role in oral carcinogenesis.