The Muscle Specific Actin antibody [HHF35] recognizes muscle specific alpha and gamma actin isomers. It does not react with non-muscle actin. Studies have shown that it recognizes the alpha actin from cardiac, skeletal and smooth muscle sources. It does not react with beta or non-smooth muscle gamma actin isomers. The antibody labels leiomyoma, leiomyosarcoma, angiomyolipoma and rhabdomyosarcoma. It does not label melanoma or lymphoma. A study has suggested [HHF35] aids the differential diagnosis of Collagenous Spherulosis and Adenoid-Cystic Carcinoma of the breast.