Some LCNECs, including tumors admixed with SCLC (“SCLC combined LCNECs”)—clustered with the majority of SCLC tumors in the classes III and IV; similarly, some SCLC tumors were part of class II that included LCNECs bearing RB1 alterations (Fig. 3a, Supplementary Fig. 11). Here, RB1 is linked to small cell lung carcinoma.