Cytokines and their role in the pathophysiology of cancer cachexia.

Cancer cachexia describes a syndrome that consists of weight loss, and abnormalities in carbohydrate, protein, and lipid metabolism, which result in a state of persistent net negative energy balance. Patients suffering from cancer cachexia have a significantly shortened survival after cancer treatment. Recent experimental studies have focused on the belief that the mechanisms of cancer cachexia involve the host's production of inflammatory cytokines, which through broad physiologic actions ultimately lead to a chronic state of wasting, malnourishment, and death. Cytokines that have been thought to play a role in the pathophysiology of cachexia include tumor necrosis factor, interleukin-1, interleukin-6, interferon-gamma and differentiation factor. It has become clear that these cytokines have overlapping physiologic activities, which makes it likely that no single substance is the sole cause of cachexia in most cancer patients. Only further investigation may make it possible to more clearly define the role of cytokines in the pathophysiology of cancer cachexia. Specific strategies to reverse the cachectic effects of these substances may then be developed to ultimately improve cancer treatment.