Based on prior studies, it is known that SCLC can rarely arise in never or light smokers via histologic transformation of lung adenocarcinoma (LUAD) either after treatment with targeted therapies or de novo (7, 8), and that RB1 and TP53 co-deficiency is a prerequisite for this conversion (9, 10). The gene discussed is RB1; the disease is small cell lung carcinoma.