Recurrent genomic alterations in aSCLC were dominated by mutations characteristic of lung carcinoids (MEN1, EIF1AX, ARID1A, and ATM), with an enrichment in the rate of ATM mutations (30%) compared with both carcinoids (8%; P = 0.008) and SCLC (3%; P = 0.0003; Fig. 2A; see Supplementary Tables S5 and S6 for full SNV data). Here, ARID1A is linked to small cell lung carcinoma.