This antibody recognizes all muscular actin isotypes. It labels myoepithelial, smooth muscle, skeletal, cardiac muscle cells and leiomyomas. It has been reported to react with pericytes and reactive myofibroblasts. Positive staining cells have been reported in some sarcomas, representing either myofibroblasts or pericytes components. Using this antibody with other myogenic markers such as smooth muscle actin, desmin and vimentin may be very helpful for differentiation of tumor from muscle origin. Clone HHF35 has been demonstrated to be a reliable marker for soft tissue tumors with muscle differentiation, i.e. leiomyomas, leiomyosarcomas, and rhabdomyosarcomas.