Clinical Significance of Salivary Biomarkers in Oral Squamous Cell Carcinoma: A Review

Background and Aim: Oral squamous cell carcinoma (OSCC) accounts for approximately 3% of all cancers worldwide, and if diagnosed early, it has a five-year survival rate of around 85%; however, a late diagnosis may decrease the survival rate to 50%. Aberrant expression of several genes is associated with the hallmarks of OSCC including uncontrolled cell proliferation, poor differentiation, invasion, metastasis, and angiogenesis. The potential of molecular biomarkers for the diagnosis, prognosis, or monitoring of the treatment efficacy in OSCC has been extensively explored during the last decades. This study aimed to review the significance of salivary biomarkers in the treatment outcome of OSCC. Materials and Methods: The articles in scientific databases including Google Scholar, ScienceDirect, Medline, and PubMed, published between 2004 and 2017, were searched by using relevant keywords including OSCC, biomarkers, diagnosis, prognosis and treatment outcome. Thirty-four articles were reviewed in this study. Results: According to the findings of the reviewed studies, several salivary biomarkers including subcutaneous adipose tissue (SAT), interleukin-8 (IL-8), Cyfra 21-1, 8-hydroxy-2-deoxyguanosine, malondialdehyde, lactate dehydrogenase (LDH), Annexin A8, ErbB2, carcinoembryonic antigen (CEA), C-reactive protein (CRP), and salivary proteomic biomarkers might be used as indicators for the detection of oral cancer and premalignant oral disease (PMOD) and as a potential marker in the prognosis of OSCC. Conclusion: Salivary biomarker analysis seems to be a major advancement in the diagnosis of OSCC, and it is a fast-developing field in scientific research. The results indicate that salivary biomarkers can be useful diagnostic and prognostic tools in OSCC.