Tumour growth and nitrogen metabolism in the host (Review)

Tumour growth is frequently associated with massive loss of body weight and negative nitrogen balance leading to cachexia, one of the worst features o f malignancy accounting for nearly two thirds of cancer deaths. At the meta bolic level, cachexia is associated with depletion of body lipid stores as well as loss of skeletal muscle protein, which is manifested as an excessiv e nitrogen loss. The present study reviews the modulations of nitrogen meta bolism in tumour-bearing conditions. In addition, the role of different med iators (such as cytokines) in the development of protein wasting is discuss ed. Particular emphasis has been given to tumour necrosis factor-alpha (TNF -alpha) which seems to have a key role in mediating changes related to nitr ogen metabolism in the tumour-bearing host.