Blood-Brain Barrier Integrity and Breast Cancer Metastasis to the Brain

Figure 4

Cancer metastasis. Pathogenesis of cancer metastasis: the process of cancer metastasis consists of sequential, interlinked, and selective steps. The outcome of each step is influenced by the interaction of metastatic cells with homeostatic factors. Each step of the metastatic process is considered rate limiting in that failure of a tumor cell to complete any step effectively terminates the process. Therefore, the formation of clinically relevant metastases represents the survival and growth of unique subpopulations of cells that preexist in primary tumors.