The primary B16F10 melanoma tumors were obtained on day 2 for immunohistochemical (IHC) staining of cleaved caspase-3 and immunofluorescent staining of Ki67 and terminal deoxynucleotidyl transferase–mediated deoxyuridine triphosphate nick end labeling (TUNEL). The gene discussed is MKI67; the disease is melanoma.