Actin pan is a kind of microfilament proteins with contractile ability, which are widely expressed in almost all myotype cells. Actin is a broad-spectrum actin, which is mainly used to detect skeletal muscle, smooth muscle, vascular smooth muscle, myocardial and myogenic tumors, including leiomyoma, leiomyosarcoma and rhabdomyosarcoma, myoepithelial cells and myoepithelioma.