A leading cause of death, cancer remains the bane of modern society and one of the most challenging research fields. Cancer is initially a localized disease that can be often treated well at a very early stage. However the vast majority of cancer deaths result from a pernicious progression of the disease, the development of distant metastases. It must therefore be a pressing research goal to focus on the pharmacological prevention of metastasis development. This review summarizes the current understanding of the cellular and molecular mechanisms of metastasis development, and suggests possible approaches for its inhibition.