Calponin

Formalin-fixed, paraffin embedded tissue block or cell block, or 1 unstained charged slide for each test requested plus 3-4 additional unstained slides cut at 4 microns. Adequate space on each slide for control tissue is required.

Calponin is a 34 kDa thin filament (F-actin) associated smooth muscle protein, involved in the regulation of smooth muscle contractility. It has been used in the identification of smooth muscle tumors and myoepithelial cells, and is most useful in the differentiation of in situ breast lesions from invasive carcinoma. Please note that calponin will stain myofibroblasts in reactive / desmoplastic stroma, in addition to myoepithelial cells, a potential pitfall in the interpretation.