TGF-α and insulin are two potent stimulators of human keratinocyte migration. Therefore, dual stimulation with both GFs was used to eliminate the factor-specific (FS) genes, such as insulin-specific genes involved in glucose uptake. TGF-β selectively inhibits TGF-α- or insulin-stimulated proliferation, and not migration, of human keratinocytes, preventing growth-specific (GS) gene expression. After two layers of “gene filtration”, motility-specific (MS) gene profiles are anticipated.