Hi Jennifer,

So called Muscle Specific Actin (which really isn't so specific), clone
HHF35, basically marks all muscle, smooth and skeletal, plus
myoepithelial cells and tumours arising from the same. Smooth Muscle
Actin stains only smooth muscle (vascular wall, GI tract, uterine wall
etc.) and not skeletal or myocardial muscle. Correct me, anyone, if I'm
wrong. I'm at home and don't have the spec sheets here.

Katri

Katri Tuomala
Anatomic Pathology
St.Joseph's Hospital
Hamilton, Ontario, Canada