Cancer Stem Cells in Human Gastrointestinal and Hepatic Cancers

Gastrointestinal cancers, including gastric, hepatic, and colorectal cancers, represent a major public health problem globally. Although the 5-year survival rate of gastrointestinal tumors has been greatly improved due to the progress of diagnostic and therapeutic strategies, therapeutic resistance and distant metastasis remain the leading causes of cancer-related death in patients with gastrointestinal tumors. Cancer stem cells (CSCs) are a population of self-renewal cells with extremely strong carcinogenic potency, contributing to the progression, metastasis, and therapeutic resistance of gastrointestinal tumors. It is generally accepted that gastrointestinal CSCs have the characteristics of self-renewal, pluripotency, tumorigenicity, metastatic potential, and therapeutic resistance. Hence, understanding the behaviors of gastrointestinal CSCs is important for characterizing the stemness landscapes of gastrointestinal tumors and developing promising strategies for the treatment of gastrointestinal tumors. This review aims to discuss the basic characteristics of gastrointestinal CSCs, existing approaches to define and isolate CSCs, and canonical molecular pathways involved in the regulation of gastrointestinal CSCs. More importantly, potential strategies targeting gastrointestinal CSCs are proposed to overcome the limitations of current therapies.