AICR	American Institute for Cancer Research
Akt BDNF	protein kinase B brain-derived neurotrophic factor
CDKN2	cyclin-dependent kinase inhibitor 2A
COX-2	cyclooxygenase 2
CTLA-4	cytotoxic T-lymphocyte-associated protein 4
CYP	cytochrome P450
DNA	deoxyribonucleic acid
EBV	Epstein–Barr virus
EGFR	epidermal growth factor receptor
EMT	epithelial–mesenchymal transition
FGF-2	fibroblast growth factor 2
GSTs	glutathione-S-transferases
HAA	heterocyclic aromatic amines
HBV	hepatitis B virus
HCV	hepatitis C virus
HHV	human herpes virus
HIF-1α	hypoxia-inducible factor 1-alpha
HIV	human immunodeficiency virus
HNSCC	head and neck squamous cell carcinoma
H. pylori	Helicobacter pylori
HPV	human papillomavirus
hTERT	human telomerase catalytic subunit
HTLV-1	human T-lymphotropic virus
IARC	International Agency for Research on Cancer
MALT	mucosa-associated lymphoid tissue
MMP	matrix metalloproteinase
MUC1	mucin 1
mTOR	mammalian target of rapamycin
nAChRs	nicotinic acetylcholine receptors
NF-κB	nuclear factor kappa B
NGF	nerve growth factor
NNN	N′-nitrosonornicotine
NOC	N-nitroso-compounds
OSCC	oral squamous cell carcinoma
PAHs	polycyclic aromatic hydrocarbons
PD-L1	programmed death-ligand 1
PNI	perineural invasion
pRb	retinoblastoma protein
PRKDC	protein kinase, DNA-activated, catalytic subunit
RNA	ribonucleic acid
ROS	reactive oxygen species
Trk	tropomyosin-related kinase
TSNA	nitrosamines
UGTs	uridine-5′-diphosphate-glucuronosyltransferases
VEGF	vascular endothelial growth factor
WCRF	World Cancer Research Fund