Figure 1.

Steps in the metastatic cascade. Parameters related to each step are shown near the description of each step. Cells in tissue are indicated in light gray, cells in blood or in transition between blood vessel and tissue are indicated in black. Local growth (step/equation 1) is needed to provide sufficient disseminated cells. Steps 2–5 are typically referred to as the metastatic cascade (equations S3-S5, S8). Step 5 has multiple outcomes, with cells surviving, but not replicating (5A), briefly or slowly replicating (5B) or rapidly replicating (5C).