Cancer metastasis is one of the most crucial problems in the field of medical research. There are two types of approaches to find a new way to treat cancer metastasis; Targeting cancer stem cells, or stromal cells in the premetastatic phase. Interactions between these two elements synergistically enhance the survival of metastatic cancer cells and promote their re-growth in the distant organ. In this review, first we summarize the recent trends in cancer stem cell studies. Then, we discuss the premetastatic phase, based on our investigations. We also review various types of tumor-associated stromal cells (monocyte/macrophage, fibroblast, adipocyte, dendritic cell, neutrophil, and natural killer cell) in relations with the tumor microenvironment formation. Moreover, dormant tumor cells and circulating tumor cells are included in this review.
Keywords: Biglycan, CCL2, CCR2, Circulating tumor cell, Dormant cell, EMT, Eph, Ephrin A1, HMGB1, Inflammation, MD-2, Metalloprotease, Organ tropism, Premetastatic microenvironment, S100A8, SAA3, TGF-β, TLR4, TNFα, VEGF.