When compared to small-cell lung cancer (SCLC), SCNCC samples demonstrated notably higher frequencies of genomic alterations in PIK3CA (24% vs. 5.1%), MYC (12.7% vs. 6.3%), ARID1A (10.1% vs. 4.2%), and MSI-High (3.1% vs. 0.004%). Here, ARID1A is linked to small cell lung carcinoma.