Immunohistochemical study of alpha-smooth muscle actin in odontogenic cysts and tumors.

Context: Myofibroblasts (MFs) are fibroblasts with smooth muscle-like features characterized by the presence of a contractile apparatus. Alpha-smooth muscle actin (α-SMA) is the actin isoform that predominates within vascular smooth muscle cells and plays an important role in fibrogenesis. MFs are metabolically and morphologically distinctive fibroblasts expressing α-SMA, and their activation plays a key role in development of the fibrotic response.