Myofibroblasts and tumor micro-environment in oral squamous cell carcinomas – a histochemical and immunohistochemical analysis

Oral squamous cell carcinoma is a multi-factorial disease and no single causative factor has been primarily held responsible.Its pathogenesis is a multistep process involving initiation, promotion and tumor progression.The tumor micro-environment, particularly the collagen characteristics, and mesenchymal cells like myofibroblasts are increasingly implicated.The present study aims to determine the myofibroblast distribution and stromal characteristics in different grades of oral squamous cell carcinoma.Total of 46 specimens of different grades of oral squamous cell carcinoma were selected from departmental archives and subjected to immunohistochemical evaluation of myofibroblasts using -smooth muscle actin marker.Parallel sections were subjected to van gieson staining to determine the characteristics of the collagen of the tumor stroma.Statistical analysis was performed for comparison between the different grades of oral squamous cell carcinoma.80% of squamous cell carcinoma specimens were positive for -smooth muscle actin.Poorly differentiated carcinoma specimens consistently demonstrated higher concentration of -SMA positive myofibroblasts and a dense stroma.There was a positive correlation between myofibroblasts and the stromal density.The interesting feature was the higher concentration of myofibroblasts in the stroma away from the tumor islands the results indicate that the effect of the myofibroblasts on the tumor stroma may play a role in the fundamental cellular processes essential for tumor progression.It is well known that TGF- dependent accumulation of collagen type 1 in tumor microenvironment is related to increased tumor invasiveness.Therefore, myofibroblasts may play a role in tumor growth and invasion.