  Using our previously developed model we demonstrate here, that (1) solid
tumor growth and cell invasion are linked, not only qualitatively but also
quantitatively, that (2) the onset of invasion marks the time point when the
tumor cell density exceeds a compaction maximum, and that (3) tumor cell
invasion, reduction of mechanical confinement and angiogenesis can act
synergistically to increase the actual tumor mass towards the level predicted
by West et al. universal growth curve.
