Myofibroblasts are responsible for contraction of granulation tissue in skin wounds. They are also present in many pathological situations, derived either from local cells in the tissue or from circulating precursor or stem cells. Because of their important role in pathological scarring and fibrosis, as well as a role in for cancer-associated myofibroblasts in tumor growth, much interest centres on the factors that regulate their differentiation and survival. Myofibroblast phenotype is regulated by the microenvironment of damaged tissue, including growth factors, the extracellular matrix, mechanical stress and mechanical signaling to which they are subjected.