PIK3CA and squamous cell carcinoma: Phosphatidylinositol-4,5-biphosphate 3-kinase, catalytic subunit alpha (PIK3CA), sex-determining region Y-related gene family 2 (SOX2), CDKN2A, TP63, fibroblast growth factor receptor 1(FGFR1), and MLL2 are the top mutant genes in squamous cell cancer; retinoblastoma 1 (RB1), E1A-binding protein p300 (EP300), MLL2, smoothened (SMO), and PIK3CA are the top mutant genes in SCLC.