Background: Oral squamous cell carcinoma is one of the most prevalent cancers worldwide. The transformation of the normal epithelial cell into a tumor cell bestows upon them certain features at the cellular and molecular level which aids in its survival and proliferation. Invasion of the altered tumor cells through the basement membrane into the connective tissue stroma and their subsequent spread and metastasis is an important prognostic indicator. Laminin-5 is a protein associated with a migratory phenotype in epithelial neoplastic cells. Along with laminin, the stromal myofibroblasts play a significant role in tumor invasion, due to its ability to modify the extracellular matrix.
Aim: To evaluate the role of laminin 5 and stromal myofibroblasts in oral epithelial dysplasia and oral squamous cell carcinoma.
Methods: Paraffin-embedded archival samples of 25 normal, 30 oral epithelial dysplasia and 30 oral squamous cell carcinoma (OSCC) were evaluated for laminin-5 and α- smooth muscle actin (SMA) using standard immunohistochemistry. Semi-quantitative assessment of the expression of laminin and alpha SMA was done in all the study samples. The area of staining and the staining intensity was evaluated in order to determine the staining index which were then statistically analyzed between the three groups.
Results: All the cases of laminin showed cytoplasmic staining in the basal cell layer and basement membrane. Expression of laminin was observed in the basal cell layer of normal and epithelial dysplasia study group and mainly around the tumor islands in OSCC group. α- SMA was seen with increasing intensity with increasing grade of the disease. Comparison of laminin expression between the three groups showed a statistically significant decrease in the staining index from normal to epithelial dysplasia to OSCC (p < 0.01). Statistical comparison of α-SMA in between the three groups using Kruskal- Wallis test showed a significant increase in the expression of α-SMA from normal to epithelial dysplasia to OSCC (p < 0.01)
Conclusion: Decreased laminin expression in the basement membrane and increased expression of α-SMA favors tumor invasion, establishment of an invasive phenotype of neoplastic cells and a permissive environment for tumor invasion.
Key words: Epithelial dysplasia, Oral cancer, Laminin, Alpha- Smooth muscle actin, Immunohistochemistry, Myofibroblasts
EXPRESSIONS OF IGF-1R, EZH2, LAMININ-5 IN LEUKOPLAKIA AND ORAL SQUAMOUS CELL CARCINOMA
