PIK3CA and head and neck squamous cell carcinoma: Based on our prior HNSCC mutation reports and publications reporting highly mutated genes in different tumor types, we select 51 highly actionable cancer related genes, including TP53, EGFR, HRAS, SRC, ABL1, PI3K, and others [3], [6], [9], [12], [15], [16], [20], [21], [24], [25], [26].