HNF4A and melanoma: To evaluate the role of β-catenin during melanoma progression we downregulated β-catenin in several well-defined human melanoma cell lines derived either from primary melanomas or from melanoma metastases [22]–[24] using either a small-molecule inhibitor of β-catenin/TCF/LEF complexes (PKF 115–584) [25] or shRNA against β-catenin (Figure 1B).