Desmin (53 kDa) exhibits a high degree of tissue specificity, its expression being predominantly confined to all types of muscle cells (cardiac, skeletal and smooth muscle). Regulation of desmin expression is stage and tissue-specific, since it is induced during terminal development of, for example, skeletal muscle cell differentiation. In skeletal en cardiac muscle cells desmin is localized in the Z-disk region and at the intercalated disk. The expression pattern of desmin in smooth muscle is much more heterogenous. Coexpression of vimentin and desmin has been observed in tumors derived from muscle tissue, i.e. rhabdomyosarcomas and leiomyosarcomas. Furthermore, during myocard dysfunction dramatic changes in the distribution of desmin have been observed.