Immunoregulatory Markers in Human Saliva – A Non-Invasive Approach in the Diagnosis of Oral Precancerous and Cancerous Lesions

Oral squamous cell carcinoma (OSCC) is the most common malignant tumor of the oral mucosa. Currently, the diagnosis of oral cancer is based on clinical examination and histopathological analysis. Numerous potential biomarkers have been suggested for oral cancer diagnosis, but the results are contradictory. A great achievement could be identification of biomarkers that indicate the early stage and progression of OSCC. Saliva is an easy to obtain biological fluid containing specific molecules for various pathologies. Some reliable saliva molecules described as oral biomarkers for OSCC are cytokines. A number of studies have shown that higher levels of the proinflammatory and proangiogenic cytokines, like IL-8, IL-6 and TNF-α in saliva could be used for early diagnosis of OSCC. Other studies have shown that the levels of some immunosuppressive cytokines (IL-4, IL-10, IL-13 and IL-1RA) are elevated in saliva in OSCC patients compared to controls. The importance of the immunoregulatory molecules as markers for OSCC is debated. Further studies are needed to identify clinically relevant biomarkers for screening and early detection of oral cancer.