[The cellular mechanisms and regulation of metastasis formation]

Recent data obtained at the junction of biochem: istry, molecular and cell biology and experimental oncology, showed that the formation of secondary foci of tumor growth during cancer progression--metastasis formation--is a highly determinate and regulated process. This process includes on the one hand the appearance of metastatic population of cells with special characteristics that allow their dissemination and seeding in distant organs and on the other.hand the formation of specific attractive micro environment in target organs. These cells show the ability to switch their motility to the most effective mode depending on the properties of the surrounding tissues (plasticity), appearance of specific receptors on the cell surface, which enhance their directed migration to target organs and acquisition of some characteristics of stem cells, allowing them to survive and reproduce in alien microenvironment. These alterations are strongly coordinated with development of a specific nichein the target organ which stimulates initiation and growth of a future metastasis, so-called premetastatic niche. In this review we analyzed recent data concerning mechanisms which regulate the emergence of metastatic population of cells, development of premetastatic niches and coordination of these processes:.