In vitro analysis demonstrated the malignant role of CK8/18 expression, indicating that various CK8/18-overexpressing cell lines, such as human lung adenocarcinoma (Chu et al, 1997), human melanoma cells (Chu et al, 1996), and mouse L cells (Chu et al, 1993), have higher migratory/invasive abilities compared with the control. This evidence concerns the gene KRT8 and melanoma.