Cancer metastases arise from a unique subpopulation of cancer cells that adapt to circumvent normal homeostatic mechanisms of cellular control. They are able to spread, invade, and thrive in non‑native environments. The clinical relevance of metastases is based not only on their lethality, but also on their unique biological characteristics, such as routes of spread, latency, metastatic tumor burden, and metastatic site. In specific clinical scenarios therapy may be based on the organ of metastatic involvement and not on the characteristics of the primary cancer. A focus on metastases has the potential to provide new scientific models to biological scientists and new therapeutic targets to clinicians.