Smooth Muscle Myosin

Smooth muscle myosin (SMM) is a smooth muscle structural protein composed of heavy chains and light chains. It can convert the chemical energy of ATP into the mechanical energy for smooth muscle contraction, which plays an important role in cell morphology maintenance and cell chemotactic migration. In clinical practice, SMM is considered as a smooth muscle biomarker with significant specificity, which can be used for the research and diagnosis of mesenchymal tumors with smooth muscle differentiation, including leiomyosarcoma, gastrointestinal stromal tumors, etc. Meanwhile, SMM is expressed in breast myoepithelial cells, which has good medical value in distinguishing benign and malignant breast lesions. It has continuous or discontinuous circular expression in benign hyperplasia and carcinoma in situ of the breast, but its expression is down-regulated or even absent in invasive breast cancer. In addition, some scholars have found that SMM heavy chains can exist in some breast cancer cells, which may be related to tumor metastasis.