EXPRESSION OF ALPHA-SMOOTH MUSCLE ACTIN IN ODONTOGENIC CYSTS AND TUMORS.

Abstract

Odontogenic cysts and tumors exhibit different degrees of aggressiveness in their biological behavior. There has been evidence that thepresence of myofibroblasts (MFs) at theinvasion front promotes tumor invasion. Our study is based on thefact that MFs are important in thebiological behavior of odontogenic cysts and tumors. To assess immunohistochemically expression of alpha-smooth muscle actin (α-SMA) of MFs in odontogenic cysts and tumors and correlate this expression to their biological behavior. Thearchival tissues collected for 1.5years were obtained from theDepartment of Oral Pathology & Microbiology, People's Dental Academy, Bhopal (India). A total of 40cases consisting of 10cases each of odontogenic keratocysts, radicular cysts, dentigerous cysts and ameloblastomas formed thestudy group. An immunohistochemical analysis of α-SMA expression and localization was carried out. Mean MF counts were thehighest in odontogenic keratocysts which was followed by ameloblastomas, entigerous cysts and radicular cysts. Weak α-SMA-expression was found in 50% of cases, moderate in 22.5% of cases, and intense- in 10% cases. MFs were arranged in thespindle, focal, or network patterns in 35; 27.5 and 20% of cases, respectively. Theanalysis revealed that theMFs were distinctly heterogeneous in distribution and pattern of arrangement. This provided persuasive evidence that stroma of these lesions harbor MFs as reflected by α-SMA immunopositive cells.