The immunohistochemical investigations of cadherin "switch" during epithelial-mesenchymal transition of tongue squamous cell carcinoma.

Oral cancer was ranked as the sixth worldwide most common cancer, but recent studies noticed an overall downward trend in its incidence. However, for tumors localized on the tongue, the incidence seems to increase. The malignant transformation of many carcinomas is associated with loss of epithelial differentiation and gain of a mesenchymal phenotype, a process known as epithelial-mesenchymal transition (EMT) which for oral squamous cell carcinomas (OSCC) could be a predictor and a prognostic factor. The aim of our study was to investigate immunohistochemically the E-cadherin/N-cadherin "switch" and vimentin expression as markers of EMT process in tongue OSCC. Thus, we analyzed 15 cases of tongue OSCC by enzymatic double immunohistochemistry using the following double pairs of antibodies: E-cadherin/vimentin and N-cadherin/E-cadherin. E-cadherin reactivity was recorded in all the investigated cases, the pattern of expression being both membranous and cytoplasmic, with the membrane pattern decreasing simultaneously with the decrease of the differentiation degree and with the increase of invasion phenotype, while the cytoplasmic pattern had an opposite behavior. Tumor parenchyma reactivity for vimentin was noticed in 73.3% and its expression was more obvious in tumor cells from the periphery of proliferative islands and in acantholytic carcinomatous cells. N-cadherin reactivity was restricted to only 33.33% of the investigated cases and its expression was prevalent in poorly differentiated forms. In conclusion, in tongue squamous cell carcinomas at the invasion front the E-cadherin reactivity decreases while vimentin expression increases, with a cytoplasmic N-cadherin reactivity in a few of the observed cases. This EMT phenotype was correlated with the decrease of differentiation degree, with the increase of the type of invasion pattern and with increasing disease' stages and thus these EMT markers could be used for prognostic stratification of such patients.