Introduction: Malnutrition is a common problem in cancer patients. Its incidence varies according to disease stage (between 15 and 90%) and is considered a possible prognostic factor for therapeutic response and survival. It is also one of the causes contributing to the increase in morbidity and mortality in patients. Tumor cachexia is defined as a nutritional defect caused by tumor growth in the patient and presents as a significant weight loss. This weight loss is mainly caused by a degradation of skeletal muscle proteins.
Conclusion: The ubiquitin-proteasome system is the most important pathway of protein degradation. As a regulatory system governing protein half-life, it is involved in the regulation of the cell cycle, signal transmission, immune system response, apoptosis, and oncogenesis. Knowledge of the molecular pathways involved in the induction of cancer-associated cachexia will favor a more rational approach to its treatment as well as possible quality of life and survival benefit for the patient.