The Role of Podoplanin in the Lymphangiogenesis of Oral Squamous Carcinomas

Oral squamous cells carcinoma (OSCC) mortality rate ranges between 29-40/100,000 inhabitants. Regional lymph node metastases occur in 30-40% cases and are associated with unfavorable prognosis and decreased survival. Recentely it was suggested that the tumor-associated lymphatic vessels formation plays an active role in metastasis proces of several human malignancies, including OSCC. In the present study we investigated comparatively podoplanin immunoexpression in OSCC in both the tumor cells and lymphatic vessels reported to clinicopathological prognostic parameters. Material and methods The study included a total of 25 cases of OSCC. We investigated clinico-pathological parameters as age, gender, tumor site, and degree of differentiation, size and depth of invasion (pT), lymph node status (pN). Histologic classification was done according to the WHO criteria. For immunohistochemical (IHC) analysis we used podoplanin (Dako, clone D2-40). As visualization system it was used LSAB2 (Dako, Redox, Romania, code K0675) and chromogen DAB (Dako, Redox, Romania, code K3468). Negative controls were obtained by omitting the primary antibodies. IHC quantification was done intensity score and by lymphatic microdensity (LVD), intratumoral and on the advancing edge. For the statistical analysis we used Student's t-tests, ANOVA, chi square and Pearson, using SPSS 10 software. Results Podoplanin immunoexpression in tumor parenchyma presented with an average of 43%, varying intensity. We found a higher intensity in weak and moderately differentiated SCC then in well differentiated ones and no difference intratumoral aand advancing edge. In relation to the degree of tumor differentiation the mean LVD D2-40 was higher in the advancing edge. SCC who presented lymph node metastasis mean values for LVD D2-4 was higher then at advancing edge and higher than those of non-metastatic carcinomas. Conclusions Podoplanin immunoexpresion suggests the involvement both in tumor growth and the acquisition of an lymphangiogenic phenotype invasive by autocrine mechanisms.