CDK4 and melanoma: We used those PR cells that are maintained in palbociclib-containing medium to assess the expression of KGA and demonstrated that KGA is not upregulated (Fig. 1F) compared to control cells while KGA is upregulated only in palbociclib-induced senescent cells, underscoring the specificity of KGA upregulation in CDK4/6i-induced senescent BrafV600E melanoma cells.