Our results corroborate an earlier in vitro study in which HUVEC endothelial cells were shown to express HB-EGF and promote the migration, in a trans-well migration assay, of EGFR-positive smooth muscle cells toward endothelial cells in an HB-EGF/EGFR-dependent manner,40 as well as an in vivo study from the same group describing decreased pericyte coverage of the tumor microvasculature in transplanted tumors following gefitinib treatment.50 This evidence concerns the gene EGFR and neoplasm.