Crucial Roles of Autophagy in Cancer Metastasis

Autophagy is an intracellular degradation system that delivers cytoplasmic components to the lysosome. Despite its apparent simplicity, recent research has revealed that it plays a wide range of physiological and pathophysiological roles, many of which are highly complex. The process of autophagy occurs through several sequential steps-sequestration, transport to lysosomes, degradation, and utilization of degradation products-with each step potentially fulfilling distinct functions. In cancer progression, metastasis represents an especially complex process. Autophagy exerts stage-specific effects: in the early stages, it functions as a tumor suppressor by preventing necrosis and limiting inflammation, whereas in advanced stages, it can promote metastasis by enabling malignant cells to disseminate into the bloodstream. This book explores the mechanisms of autophagy and its role in driving cancer metastasis, with particular attention to how it enhances tumor aggressiveness in a process-dependent manner.