Desmin is an intermediate filament protein that is primarily found near the Z line in sarcomeres, which are structural units of muscle cells. Both desmin and vimentin are characteristic markers of mesenchymal cells.

The desmin antibody is capable of detecting a protein expressed by cells of normal smooth, skeletal, and cardiac muscles. Studies using light microscopy have shown that desmin is predominantly located at or near the periphery of Z lines in striated muscle fibrils. In smooth muscle, desmin serves to connect cytoplasmic dense bodies with membrane-bound dense plaques.

The desmin antibody reacts with various types of tumors and cells. It can be used to identify desmin-positive components in leiomyomas (benign smooth muscle tumors), rhabdomyoma (benign skeletal muscle tumors), and the perivascular cells of glomus tumors of the skin if they have a myogenic nature. By demonstrating the myogenic components or derivation of tumors, the desmin antibody assists in characterizing the presence of muscle-related elements.