MKI67 and cancer: We also showed that photothermal therapy induced a direct effect on cancer cells with significant inhibition of proliferation (21 ± 1% vs. 44 ± 1% Ki67-positive cells/hpf, respectively, P < 0.01), and significant tumor cell apoptosis (10 ± 1% vs. 7 ± 1% cleaved caspase3-positive cells/hpf, respectively, P < 0.05).