Cancer stem cells and tumor metastasis (Review)

Previous studies have shown that tumors can induce angiogenesis and lymphangiogenesis, which plays an important role in promoting hematogenous and lymphogenous spread. In recent years, the cancer stem cell (CSC) theory has emerged as an attractive hypothesis for tumor development and progression. The theory proposes that one small subset of cancer cells has the characteristics of stem cells. These CSCs have the capability of both self-renewal and differentiation into diverse cancer cells, which play a decisive role in maintaining capacity for malignant proliferation, invasion, metastasis, and tumor recurrence. CSCs are involved in tumor metastasis, however, the details, and the possible relationship of CSCs, angiogenesis, lymphangiogenesis, and tumor metastasis is still ambiguous. The aim of this report is to summarize current studies of CSCs and tumor metastasis at the cellular level, with the goal of bringing new insights into understanding the role of CSCs in tumor metastasis.