Differential transendothelial migrations of A375, 1205LU and SLM8 cell lines. A HUVEC cells were seeded on type I collagen-coated Transwell culture inserts. DiO-labelled melanoma cells were added to the upper chamber and allowed to migrate for 48 h. Cells on the lower face of the inserts were fixed and labeled with DAPI prior to their observation under an epifluorescence microscope. B The histograms represent the quantification of the data obtained from 3 independent experiments, and all the experiments were performed in duplicate. The A375 cell line was considered here as having a 100% transmigration efficiency.