Metastasis: a therapeutic target for cancer.

Metastasis remains the major driver of mortality in patients with cancer. Our growing body of knowledge regarding this process provides the basis for the development of molecularly targeted therapeutics aimed at the tumor cell or its interaction with the host microenvironment. Here we discuss the similarity and differences between primary tumors and metastases, pathways controlling the colonization of a distant organ, and incorporation of antimetastatic therapies into clinical testing.