On the other hand, the majority of melanomas in the other three groups did not have mutations in BRAF or NRAS but instead had increased copy number of the downstream genes CCND1 or CDK4. These findings implicate CDK4 and CCND1 as independent oncogenes in melanomas presenting this genetic background (absence of mutations in BRAF and NRAS). The gene discussed is CDK4; the disease is melanoma.