Movie S1.

XYZ stack of GFP-expressing monocytes in a tumor-bearing mouse imaged over 140 minutes. Note that high GFP (Cx3cr1^GFP/WT high) expressing cells are stationary and do not migrate, however low GFP expressing cells (Cx3cr1^GFP/WT low) are migratory. The cells appear to migrate in random directions and along vessels. Frame rate = 10 fps.