ASCL1 and small cell lung carcinoma: We found positive NOTCH1-ICD IHC staining in 29% (n = 56 of 193) of SCLC tissues (Figure 9B), including 29% (n = 44 of 154) of ASCL1+ SCLC tumors (Supplemental Figure 12C), demonstrating intertumor heterogeneity of active NOTCH1 signaling in SCLC.