CDK4 and melanoma: Analysis of the mutational status of the panel of cell lines using the COSMIC database (http://cancer.sanger.ac.uk/cancergenome/projects/cell_lines/) and the Cancer Cell Line Encyclopedia (http://www.broadinstitute.org/ccle), suggest that mutations in CDK4 or p16INK4A do not predict response or resistance, as only one of the melanoma cell lines (SK-MEL-28) has a mutation in CDK4 and there are no reported mutations in p16INK4A in these cell lines.