癌症恶病质，或癌症患者体重意外减轻，是一种多器官、多因素的综合征，其病因复杂且很大程度上未知。然而，代谢功能障碍和炎症仍然是癌症相关消瘦的标志。虽然恶病质表现为肌肉和脂肪组织损失，但胃肠道扰动可能是营养吸收受损和免疫激活肠道菌群失调的前线。过去 2 年来，对肠道微生物群的研究呈爆炸式增长，证明了肠道组织的多个轴。然而，脂肪和骨骼肌消耗以及肠道微生物群与癌症之间的联系才刚刚开始被了解。此外，最常用的抗癌药物（例如化疗、免疫检查点抑制剂）会对肠道稳态产生负面影响，可能会加剧浪费并导致患者预后不良和生存率下降。在当前的综述中，我们 1) 强调我们目前对恶病质发生的微生物变化的理解，2) 讨论微生物变化如何导致脂肪和骨骼肌消耗，3) 概述在检查恶病质的作用时所需的研究设计考虑因素癌症引起的恶病质中的微生物群。

Cancer cachexia, or the unintentional loss of body weight in cancer patients, is a multi-organ and multi-factorial syndrome with a complex and largely unknown etiology; however, metabolic dysfunction and inflammation remain hallmarks of cancer-associated wasting. While cachexia manifests with muscle and adipose tissue loss, perturbations to the gastrointestinal tract may serve as the front line for both impaired nutrient absorption and immune activating gut dysbiosis. Investigations into the gut microbiota have exploded within the past 2 decades, demonstrating multiple gut-tissue axes; however, the link between adipose and skeletal muscle wasting and the gut microbiota with cancer is only beginning to be understood. Further, the most used anti-cancer drugs (e.g. chemotherapy, immune checkpoint inhibitors) negatively impact gut homeostasis, potentially exacerbating wasting and contributing to poor patient outcomes and survival. In this current review, we 1) highlight our current understanding of the microbial changes that occur with cachexia, 2) discuss how microbial changes may contribute to adipose and skeletal muscle wasting, and 3) outline study design considerations needed when examining the role of the microbiota in cancer-induced cachexia.