(A) Percentage transendothelial migration in microvascular network devices at 6 hours when tumor cells are treated with function-blocking antibodies for various α and β subunits (n=3 experiments, 3 devices per condition, *p<0.05, **p<0.01, ***p<0.001, bars represent mean +/− SEM). (B) Western blot analysis of alpha 3 and alpha 6-integrin individual knockdowns and co-knockdowns in MDA-MB-231 via siRNA. (C) Kinetics of TEM in microvascular networks following the same regions at 0, 6, 12 and 24 hr after tumor cell seeding.