George et al. (2015) analysed 71 of 152 fresh-frozen clinical tumour specimens from SCLC patients by genome sequencing, and found the prevalence of Notch mutations in SCLC has been estimated to be in the range of 25%–28%, resulting in a loss of function of the Notch signaling pathway (Ardeshir-Larijani et al., 2018). Specifically, analysis of clinical trial samples confirmed that the Notch inhibitory ligand, DLL3, is expressed in more than 75% of SCLC, and that the majority of SCLC patients have high levels of DLL3 expression (Hu et al., 2022). Here, DLL3 is linked to small cell lung carcinoma.