PIK3CA and head and neck squamous cell carcinoma: The presence of mutations in TP53, CDKN2A, PIK3CA and Phosphatase and tensin homolog (PTEN) which are involved in the receptor tyrosine kinase/RAS/Phosphoinositide 3 kinase (RTK/RAS/PI3K) pathway; Notch homolog 1, translocation-associated (Drosophila) (NOTCH1) which is linked with squamous differentiation; (F-Box And WD Repeat Domain Containing 7) FBXW7 tumor suppressor gene which has a downstream effect on NOTCH1, were the initial mutations detected amongst HNSCC (Beck and Golemis, 2016; Litwin et al., 2017; Yeh et al., 2018; Gillison et al., 2019a; Huang et al., 2019).