DLL3 and neoplasm: SCLC cells express Notch inhibitors delta like non-canonical Notch ligand 1 (DLK1) and DLL3 (DLL3 is expressed as a neoantigen on the surface of some SCLC cells) or have inactivating mutations in the Notch pathways (Gazdar et al., 2017), leading to inactivation of the tumor suppression.