Association of E-cadherin & vimentin expression with clinicopathological parameters in lingual squamous cell carcinomas & their role in incomplete epithelial mesenchymal transition.

Background & Objectives: Lingual squamous cell carcinomas (SCC) pose a major public health burden in India. Epithelial-mesenchymal transition (EMT) is the conversion of an epithelial cell to a mesenchymal phenotype at the invasive front (IF) enhancing invasiveness of these cells which may be studied using immunohistochemistry. The objective of this study was to assess the expression of E-cadherin and vimentin at the IF, and their correlation with the histological risk assessment score, clinicopathological parameters and lymph node metastasis.

Methods: Thirty consecutive untreated patients diagnosed as lingual SCC who underwent hemiglossectomy over one year formed the study group. The immunohistochemical expression of E-cadherin and vimentin in the periphery as well as the centre of tumour islands was correlated with clinicopathological parameters, Brandwein-Gensler risk assessment score and lymph node metastasis, along with a correlation between the coexpression of two markers at the IF.

Results: Loss of E-cadherin expression was seen at IF in 83.3 per cent (25/30) cases. Out of these, 20 per cent (5/25) showed a corresponding gain in vimentin expression (complete epithelial-mesenchymal transition) and 80 per cent (20/25) did not. Overall, 16.6 per cent (5/30) cases showed complete EMT. However, no correlation between E- cadherin and vimentin expression at the IF was found. No statistical significance was found between E-cadherin loss and vimentin gain at the IF, with the various parameters or the risk score.

Interpretation & Conclusions: The present study suggests that the cells at IF may metastasize even without a gain in vimentin expression (without classical EMT), as cohesive clusters showing incomplete EMT (E-cadh-/Vim-).