Muscular dystrophies (MD) represent a genetically and clinically heterogeneous group of inherited diseases of the skeletal muscle characterized by a progressive degeneration of functional muscle tissue and its transformation into fat and connective tissue. Patients suffer from progressive muscle weakness, which often causes a diminished life expectancy. The different MD forms are each based on a defective or missing expression of a protein due to a mutation in an MD gene. In this study, the focus is on the proteins dystrophin and dysferlin, which are associated with Duchenne muscular dystrophy (DMD) and limb-girdle muscular dystrophy type 2B (LGMD2B). In corresponding mouse models of these two MDs, a frequent occurrence of malignant, muscle-associated sarcomas in the advanced stage of disease is observed. This suggests that both dystrophin and dysferin have their central role in the integrity of the muscles as well as they have a tumor suppressor function1. For reasons which are not yet understood, re-expression of the respective deleted gene product occurs in these tumors, which suggests a causal link with the tumorgenesis. In the present work, this phenomenon is investigated by using immunohistochemical methods with regard to the cellular localization and its distribution within the corresponding sarcoma. In addition, a quantitative, as well as qualitative characterization of these proteins is performed via Western blot. The results should help to understand the underlying molecular mechanism of this tumor-specific phenomenon.