CDKN2A and squamous cell carcinoma: Squamous cell carcinomas had a significantly higher prevalence of genomic alterations in 43 genes including TP53 (81.9% vs 48.7%), CDKN2A (16.3% vs 4.4%), PIK3CA (11.6% vs 4.2%), RB1 (6.6% vs 4.1%), and NFE2L2 (13% vs 1.2%) (Figure 1B; Supplementary Table S1).