The Cellular Microenvironment and Metastases
Summary of Key Points
• Metastases are responsible for more than 90% of all cancer-related deaths.
• Gene mutations, the tumor microenvironment, and host cells drive the metastatic spread of tumor cells.
• Metastasis can be subdivided into four steps: invasion, intravasation, survival in circulation, and extravasation.
• Colonization of metastatic tumor cells requires the ability to proliferate in a foreign tissue and stimulate angiogenesis.
• The formation of a premetastatic niche is essential for the growth of extravasating metastatic tumor cells.
• Organ specificity of tumor metastases is determined both by blood flow and tissue-specific factors.
• Primary tumors possess stem cells that can recapitulate the tumor from a single cell, and a subset of these cancer stem cells may inherently possess altered gene expression changes with increased metastatic potential.
