CLIC4 and Merkel cell skin cancer: Fig. 4C shows that migration of MCPyV-positive MCC cell lines were significantly reduced compared with control (n = 3, p < 0.001), upon treatment with either NPPB or CLIC1 depletion, suggesting that MCPyV-positive MCC cell line migration is similarly Cl− channel dependent. Together these data demonstrate that CLIC1 or CLIC4 depletion specifically inhibits MCPyV ST–induced motility, suggesting that these Cl− channels mediate the effects observed for pharmacological Cl− channel modulation.