Second, although Ki67 proliferation index in all aSCLC samples was in the range of conventional SCLC (50%–100%), these tumors were enriched in Ki67 rates at the lower end of this spectrum compared with other SCLC (mean Ki67 rate 69% vs. 87%, respectively; P < 0.0001). The gene discussed is MKI67; the disease is small cell lung carcinoma.