Table 2.

Potential biomarkers in head and neck cancers

Major Classes	Member	Function
Cell-cycle regulation	p16INK4A	A tumor-suppressor gene regulating senescence and cell-cycle progression
	TP53	A tumor-suppressor gene regulating cell-cycle progression and cell survival
	PTEN	A tumor-suppressor gene regulating signaling pathways controlling cell proliferation and apoptosis
	Rb	A tumor-suppressor gene regulating cell-cycle progression and apoptosis
	Cyclin D1	A proto-oncogene regulating cell-cycle progression
Signal transduction	EGFR	A transmembrane TK that acts as a central transducer of multiple signaling pathways
	VEGF	A transmembrane TK that promotes the proliferation, migration, and survival of endothelial cells during tumor growth
Extracellular matrix degradation	MMPs	A family of zinc-dependent proteolytic enzymes that degrade the basement membrane and other components of the extracellular matrix
Prostaglandin metabolism	Cox-2	A catalytic enzyme that decreases apoptosis, increases inflammation and immunosuppression, and enhances the potential for tumor progression
Oncoviruses	EBV	A causative agent for most nasopharyngeal carcinomas
	HPV	A causative agent for most oropharyngeal cancers

Abbreviations: EBV, Epstein-Barr virus; EGFR, epidermal growth factor receptor; HPV, human papillomavirus; MMPs, matrix metalloproteinases; Rb, retinoblastoma; TK, tyrosine kinase; TP53, tumor protein 53; VEGF, vascular endothelial growth factor.