Xie H, Boland JM, Maleszewski JJ, et al. - Because delta-like protein 3 (DLL3), an inhibitory Notch ligand, is the target for rovalpituzumab tesirine in development for the treatment of small cell lung cancer (SCLC), researchers analyzed the expression of DLL3, its reproducibility and prognostic role in pulmonary neuroendocrine tumors. For resected pulmonary neuroendocrine tumors (1995–2017), institutional pathology files have been explored. They categorized the expression of DLL3 (clone SP347) as high (≥ 50% of tumor cells) or low (< 50%). The study sample consisted of 157 patients with a median age of 62.2 years (range 23.2–88.1) involving 59 men. Findings suggested an association of high DLL3 expression with better overall survival in SCLC but not after adjusting for age, tumor size and stage. The authors concluded that DLL3 expression is reliably quantifiable by pathologists and is extremely expressed in most SCLC and a subset of carcinoid tumors, making it an appealing target for therapy with anti-DLL3.