To assess changes in the muscle proteome that due to tumor burden and dexamethasone treatments and compare proteomic changes that occur in atrophy due to tumor burden and dexamethasone treatment with atrophy caused by aging. Regulators of muscle atrophy induced by diseases such as cancer or drugs such as dexamethasone are largely unknown. We would therefore like to determine the proteomic signature of atrophying muscle caused by tumor burden (LLC cell injected mice) and dexamethasone treatment in order to examine possible biomarkers and regulators of muscle atrophy. We would also like to compared the proteomic signature of different modes of muscle atrophy to determine similarities and differences in the possible biomarkers and regulators.