PIK3CA gene amplification is found in 46% of squamous cell carcinomas, with a correlation between PIK3CA genomic copy number and PIK3CA and GLUT1 mRNA expression.49 Squamous cell carcinomas exhibit increased AKT signaling activities compared to adenocarcinomas in terms of higher expression of p‐AKT, and the downstream targets p‐4EBP1 and p‐S6, which promote HIF‐1α mRNA translation.49, 50 AKT is activated by hypoxia and this pathway is relevant for cell survival of hypoxia. This evidence concerns the gene PIK3CA and adenocarcinoma.