Correlation between invasion mode and the histologic risk assessment model in oral squamous cell carcinoma

The histologic risk assessment (HRA) model was proposed to assess clinical outcome of oral squamous cell carcinomas (SCCs), and its prognostic value has been confirmed in several studies, but its underlying molecular mechanisms has not been fully investigated. The objective of this study was to evaluate the association between immunohistochemical invasion mode of head and neck SCC and the HRA grading system.

The HRA model consisting of risk scores (RSs), based on perineural invasion (PI), lymphocytic infiltration (LI), and worst pattern of invasion (WPOI), was used for grading 80 samples of head and neck SCC, followed by immunohistochemical staining with antibodies against E-cadherin, N-cadherin, and podoplanin. The two major invasion modes were considered as epithelial-mesenchymal-transition (EMT) and collective cell invasion (CCI) with profiles of E-cadherin^-/N-cadherin+/podoplanin^- and E-cadherin+/N-cadherin^-/podoplanin⁺, respectively. All other immunohistochemical profiles were classified as partial/incomplete EMT. Statistical analysis was performed by Kruskal-Wallis and Mann-Whitney U tests (P < 0.05).

Invasion pattern was significantly different among the three RSs (P = 0.01) and across the different scores of LI (P = 0.03) but not perineural invasion (PNI) (P = 0.07) and WPOI (P = 0.70).

Based on our results, it seems that there is a difference in EMT, CCI, and partial/incomplete EMT among the variables of the HRA model which might help clarify its functioning system.