Induction of epithelial-mesenchymal transition and loss of podoplanin expression are associated with progression of lymph node metastases in human papillomavirus-related oropharyngeal carcinoma.

Objective: To examine human papillomavirus (HPV) status, the expression of podoplanin and epithelial-mesenchymal transition (EMT) markers and lymphatic vessel counts (LVC) in oropharyngeal squamous cell carcinoma (OPSCC) tissues, and to evaluate whether these factors were associated with survival and nodal status.

Results: A total of 53 OPSCC specimens were evaluated for HPV status and expression of proteins such as podoplanin and EMT markers by immunohistochemistry. E-cadherin-negative and vimentin-positive specimens were defined as EMT-positive. Twenty-two OPSCCs were HPV-positive. There was significant progression of nodal status in patients with HPV-positive tumours (P = 0.0475). HPV-positive cases had significantly lower expression of podoplanin (P = 0.0016) and were more frequently EMT-positive (P = 0.0172). Podoplanin-negative cases and EMT-positive cases showed significantly more advanced nodal status than their respective counterparts (P = 0.0082 and P = 0.0186, respectively). LVC correlated with neither HPV nor nodal status. Multivariate analyses revealed that HPV infection was an independent marker of longer disease-specific survival (P = 0.014).

Conclusions: HPV-positivity in OPSCC was associated with loss of podoplanin expression and with EMT induction, which resulted in progression of nodal status. The mechanisms leading to an improved prognosis in HPV-positive OPSCC patients requires elucidation, as this is inconsistent with the aggressive phenotype with lymph node metastases.