癌症惡病質之機制與運動訓練的效果

癌症惡病質會明顯降低癌症病患存活率與生活品質，其特徵為肌肉量與體重降低。除了食慾不振，降低肌肉蛋白合成、增加肌肉蛋白降解與增加細胞凋亡都會導致惡病質病患的肌肉量下降，然而造成癌症惡病質的機制還不是非常清楚。本文回顧造成癌症惡病質之機制，包含肌肉生長抑制素（myostatin）、腫瘤壞死因子α（tumor necrosis factor α）、蛋白分解因子（proteolysis-inducing factor）、介白素6（interleukin-6）及血管收縮素II（angiotensin II），及其下游之訊息傳遞路徑，並討論運動訓練對癌症惡病質之影響。

Cachexia, characterized by progressive muscle wasting and weight loss, significantly reduces the survival rate and the quality of life of cancer patients. In addition to anorexia, reduced protein synthesis, enhanced protein degradation, and increased apoptosis have been shown to contribute to the muscle mass loss in cachectic patients. However, the mechanisms underlying cancer cachexia remain unclear. This article reviews underlying mechanisms of cancer cachexia, such as myostatin, tumor necrosis factor α, proteolysis-inducing factor, interleukin-6, and angiotensin II as well as their downstream signaling pathways. The effects of exercise training on counteracting cancer cachexia were also discussed in this review.