Metabolic Boyden chamber assay demonstrating differences in invasiveness among 6 different cancer cell lines that included 3 human breast cancer lines (MDA-MB-435 [A], MDA-MB-231 [B], and MCF-7 [C]), 1 rat prostate cancer cell line (MatLyLu [D]), and 2 human prostate cancer cell lines (PC-3 [E] and DU-145 [F]) at approximately 47 h. T1-weighted MR images show the bright Matrigel layer, which is significantly degraded by all cell lines except MCF-7. (Adapted with permission of (70).)