Palbociclib for treatment of metastatic melanoma with copy number variations of CDK4 pathway: case report

The mortality associated with unresectable or metastatic melanoma remains high despite of the emergence of new anti-tumor agents. In this case report, we present two metastatic melanoma patients with copy number variations (CNVs) of cyclin dependent kinase 4 (CDK4) pathway-related genes, who had failed in previous chemotherapy or immunotherapy, were treated with CDK4/6 inhibitor palbociclib and achieved tumor control for over 6 months. The copy number of CDK4, CCND1 and P16^INK4a of one patient was 3.6, 3, 2 copies, and for the other patient, the copy number was 3, 2, 1 respectively. It indicates that CDK4 may be a potential target for melanoma.