Molecular mechanisms of cancer cachexia. Cancer cachexia is a complex, multifactorial syndrome characterised by a critical weight loss, anorexia, asthenia and anaemia. Most of the patients with advanced cancer suffer from cancer cachexia. The cachectic state is closely associated with progressive expansion of the tumour and leads to a malnutrition status due to the induction of anorexia and decreased food intake. In addition, the competition for nutrients between the tumour and the host leads to malnutrition state, too, which promotes severe metabolic disturbances in the host, including hypermetabolism which leads to an increased energetic inefficiency. Although, the search for the cachectic factors has a long history, we are still far away from knowing the complete answer. The main aim of the present paper is to summarise the different catabolic mediators involved in cancer cachexia. Better understanding of the pathomechanism of cancer cachexia can lead to the discovery of new, effective strategies of the therapy for the future.