In HNSCC, the hepatocyte growth factor/mesenchymal-epithelial-transition factor (HGF/c-MET) pathway promotes PI3K/Akt, RAS/MAPK, STAT3, and Src/NF-κB intracellular signaling, resulting in cancer cell proliferation and apoptosis avoidance, followed by extensive growth and metastasis [56,57]. Here, PIK3CA is linked to head and neck squamous cell carcinoma.