Migration/invasion assay. (A) Schematic presentation of an Fluoroblock BioCoat™ invasion chamber (BD) composed of a Matrigel™ coated transwell insert containing an 8 μm pore size membrane. The Matrigel matrix locks the pores of the membrane and therefore blocks non invasive cells from migrating. Invasive cells can degrade this basement membrane reconstitution and migrate through the pores. (B) Cells have been seeded at high density into the upper chamber. Migration was stimulated by a serum gradient. After 22 hours the amount of migrated cells has been measured with the Cytofluor4000 fluorescence reader (MTX Lab Systems) from the bottom after cell labelling with calcein (BD), a staining dye for vital cells only. The FluoroBlok™ membrane efficiently blocked the transmission of light into the upper chamber, therefore the measured signal derived from migrated cells only. Although all cells migrated efficiently, no difference could be detected by comparing Hs578TEpCAM and MDA-MB-231EpCAM cells with their respective empty vector control lines (set as 100%).