Cytokines in the pathogenesis of cancer cachexia

The aim of the present review is to summarize and update the role of different cytokines in the pathogenesis of cancer cachexia and to provide therapeutic strategies based on cytokine action.

Cancer cachexia is a syndrome characterized by a marked weight loss, anorexia, asthenia and anemia. The cachectic state is invariably associated with the presence and growth of the tumor and leads to a malnutrition status due to the induction of anorexia or decreased food intake. In addition, the competition for nutrients between the tumor and the host leads to an accelerated starvation state which promotes severe metabolic disturbances in the host, including hypermetabolism, which leads to an increased energetic inefficiency. Different cytokines are clearly implicated in this process, possibly being responsible for anorexia, hypermetabolism and many other metabolic abnormalities, such as muscle proteolysis and apoptosis.

Although the search for the cachectic factor(s) started a long time ago, and although many scientific and economic efforts have been devoted to its discovery, we are still a long way from knowing the whole truth. A lot of progress has been made, however, in understanding the role of different cytokines - tumor necrosis factor and IL-6 in particular - in muscle wasting associated with cancer cachexia, perhaps the most paradigmatic feature of this complex syndrome.