Genetic alterations in head and neck squamous cell carcinoma: The next-gen sequencing era

Figure 1 The Rb/CDKN2A (p16) pathway. (A) Black arrows demonstrate the normal Retinoblastoma (Rb) pathway. Human papilloma virus (HPV) viral oncoprotein E7 increases Rb degradation, leading to cell cycle activation and upregulation of upstream p16, which serves as a biomarker to detect HPV positive head and neck squamous cell carcinoma (B) Loss of p16 tumor suppressor activity contributes to tumorigenesis.

Figure 2 The Ras/PI3K pathway. EGFR: Epidermal growth factor receptor; Mek: Methyl ethyl ketone; MTOR: Mammalian target of rapamycin.