Table 1.

Diagnostic and Screening biomarkers.

References	Cancer Type	Biomarker Name-Gene	Function	Sample Type	Biomarker Behavior	Application
[21]	Oral and oropharyngeal	MiR-9	Non-coding RNA implicated in the modulation of gene expression, tumor suppression through inhibition of cellular pro-proliferation and modulation of PTEN.	Tissue	Promoter hypermethylation/sites 1 and 3.Low expression.	Diagnosis
[22]	Oral	EDNRB	It encodes the B-type endothelin receptor (G protein-coupled receptor) that triggers a phosphatidylinositol-calcium second messenger system.	Saliva	Promoter hypermethylation in 40% of malignant samples.	Screening, Diagnosis
[22]	Oral	DCC	Tumor suppressor, encodes a transmembrane protein with structural homology to NCAM, which is associated with the differentiation of epithelial and neuronal cells.	Saliva	Promoter hypermethylation in 40% of malignant samples.	Screening, Diagnosis
[23]	HNSCC	MED15/ PCQAP	Encodes a cofactor with pleiotropic activity, important for the formation of the RNA polymerase II complex, which is involved in the expression of all protein-coding genes, attenuation of at least one of the signaling pathways (TGFβ/Activin signaling).	Tissue, saliva	Specific methylation patterns in the promoter.	Screening, Diagnosis
[24]	HNSCC	ZNF14, ZNF160, ZNF420	Members of the zinc finger gene family.	Tissue, saliva	Differential methylation pattern.	Diagnosis
[25]	HNSCC	FAM135B	Involved in the maintenance of the nucleolus, cell proliferation, cell differentiation, and apoptosis.	Tissue	Hypermethylation. Low expression.	Diagnosis
[25]	HNSCC	ZNF610	Involved in the maintenance of the nucleolus, cell proliferation, cell differentiation, and apoptosis.	Tissue	Hypermethylation. Low expression.	Diagnosis
[25]	HNSCC	HOXA9	Involved in the maintenance of the nucleolus, cell proliferation, cell differentiation, and apoptosis.	Tissue	Hypomethylation. High expression.	Diagnosis
[25]	HNSCC	DCC	Involved in the maintenance of the nucleolus, cell proliferation, cell differentiation, and apoptosis.	Tissue	Hypomethylation. High expression.	Diagnosis
[26]	HNSCC	HOXA9	Encodes a transcription factor. HOX genes regulate and specify different cell types during embryonic growth, and have important functions in the modulation of the sensitive balance between cell proliferation and differentiation during cancer development.	Tissue	Promoter hypermethylation.	Screening, Diagnosis
[27]	HPV+ OPSCC	KCNA3, EMBP1, CCDC181, DPP4, ITGA4, BEND4, CTNND2, ELMO1, SFMBT2, C1QL3, MIR129-2, ATP5EP2, OR6S1, NID2, HOXB4, ZNF439, ZNF93, VSTM2B, ZNF137P and ZNF773	ITGA4: on the cell surface, promotes migration and adhesion to the microenvironment in chronic lymphocytic leukemia. NID2: component of the basement membrane that stabilizes the extracellular matrix (ECM) network. Suppresses migration and blocks metastasis by downregulating the EGFR/AKT and integrin/FAK/PLCγ pathways. HOXB4: a hematopoietic transcription factor, downregulates the expression of Prdm16, which is a proto-oncogene necessary for self-renewal and preservation of mouse hematopoietic stem cells. SFMBT2: tumor suppressor, negatively regulates migration and invasion by targeting MMP-9 and MMP-26. MIR129-2: tumor suppressor, inhibits migration and invasion by directly inhibiting HMGB1. DPP4 and CTNND2: act both as tumor suppressors and as markers of tumor invasiveness, depending on the type of tumor. KCNA3: its knockdown markedly suppresses cell proliferation and increases apoptosis. EMBP1: related to ER-positive breast cancer and lower grade breast tumors. ZNF93: implicated in the DNA repair pathway following DNA damage by chemotherapy. Little is known about six candidates (ATP5EP2, OR6S1, ZNF439, VSTM2B, ZNF137P, ZNF773). ZNF439, ZNF137P, ZNF773: belong to the zinc finger protein group, members of which have previously been shown to have tumor-suppressive activity.	Tissue	20 differentially DMRs → hypermethylation.	Screening
[28]	HNSCC	PROM1/CD133	Encodes a pentaspan membrane glycoprotein, which is frequently found in adult stem cells.	Tissue	Promoter hypermethylation. Low expression.	Diagnosis
[29]	HNSCC	CTHRC1	Encodes an extracellular matrix protein, modulating tumor microenvironment	Tissue	Promoter hypomethylation. High expression.	Diagnosis
[30]	HNSCC	PLAU	Encodes a protease implicated in apoptosis, epithelial-mesenchymal transition (EMT), and the Ras/MAPK pathway.	Tissue	Hypomethylation. High expression.	Diagnosis
[31]	HNSCC	MTHFD1L	Encodes a cytoplasmic enzyme participating in the formation of tetrahydrofolic acid (THF) within mitochondria.	Tissue	Promoter hypomethylation. High expression.	Diagnosis
[32]	HNSCC	Opioid receptor mu 1(OPRM1)	Encodes an opioid receptor (G-protein-coupled receptor).	Tissue, plasma	Hypermethylation.	Screening
[32]	HNSCC	Opioid-related nociceptin receptor 1(OPRL1)	Encodes an opioid receptor (G-protein-coupled receptor).	Tissue, plasma	Hypermethylation.	Screening
[33]	HNSCC	XPR1	Encodes a cell surface receptor for certain types of murine leukemia viruses, which plays an essential role in maintaining intracellular phosphate homeostasis by mediating phosphate export from the cell.	Tissue	Promoter hypomethylation. High expression.	Diagnosis