Moreover, deleterious somatic variants in HNSCC hallmark genes: TP53, NOTCH1, CDKN2A, CASP8, PIK3CA, USP6, MLL2, HLA-A, FANCA, PDE4DIP, and FAT1 were also identified [29], [30]. The gene discussed is PIK3CA; the disease is head and neck squamous cell carcinoma.