CDK4 and melanoma: Not only were these findings meaningful, opening new windows for cancer therapy, but also, in particular in the Damía Tormo studies, was the murine model used very suited, whereupon mice overexpressing hepatocyte growth factor (HGF) and carrying an oncogenic mutation in the cyclin-dependent kinase-4 [(CDK4)R24C] developed invasive melanomas in the skin following neonatal exposure to carcinogenics.