Despite the stark differences in OS between SCLC-I and SCLC-P in the atezolizumab arm (Supplemental Figure 4, B and C), we observed nearly all SCLC-I (82%, n = 40 of 49) and SCLC-P (90%, n = 19 of 21) tumors to have high expression of NOTCH1 (Figure 2A). This evidence concerns the gene NOTCH1 and small cell lung carcinoma.