Special Issue "Saliva and Oral Diseases"

Advances in the Diagnosis, Monitoring, and Progression of Oral Cancer through Saliva: An Update

The early detection of cancer, and in particular oral cancer, has been a priority objective of study in recent years. Saliva has been proposed as an easy-to-obtain means of providing the necessary information to diagnose malignant lesions in the oral cavity, since it can be obtained very easily and completely noninvasively. There are a number of molecules, known as biomarkers, which may be involved in the malignant transformation of oral lesions, and which have different natures. The involvement of proteins (“proteomics”), metabolites (“metabolomics”), and even certain genes in the structural changes of altered tissue has been investigated in order to establish validated parameters for the early diagnosis of oral cancer. In addition, the development of new analytical assay methods that can reduce costs and obtain better results in terms of sensitivity and specificity has been a key point in recent research in this field. Even though there are numerous biomarkers with results showing high sensitivity and specificity, there is still a need for more studies, with a larger sample and with analytical methods that can constitute a real advance in time and cost. Although salivary biomarkers are a promising new diagnostic tool for oral cancer, for the moment they do not replace biopsy as the “gold standard”.

Salivary Osteopontin as a Potential Biomarker for Oral Mucositis

Osteopontin (OPN), a multifunctional phosphoglycoprotein also presents in saliva, plays a crucial role in tumour progression, inflammation and mucosal protection. Mucosal barrier injury due to high-dose conditioning regimen administered during autologous and allogeneic peripheral stem cell transplantation (APSCT) has neither efficient therapy nor established biomarkers. Our aim was to assess the biomarker role of OPN during APSCT, with primary focus on oral mucositis (OM). Serum and salivary OPN levels were determined by ELISA in 10 patients during APSCT at four stages of transplantation (day -3/-7, 0, +7, +14), and in 23 respective healthy controls. Results: There was a negative correlation between both salivary and serum OPN levels and grade of OM severity during APSCT (r = -0.791, p = 0.019; r = -0.973, p = 0.001). Salivary OPN increased at days +7 (p = 0.011) and +14 (p = 0.034) compared to controls. Among patients, it was higher at day +14 compared to the time of admission (day -3/-7) (p = 0.039) and transplantation (day 0) (p = 0.011). Serum OPN remained elevated at all four stages of transplantation compared to controls (p = 0.013, p = 0.02, p = 0.011, p = 0.028). During APSCT elevated salivary OPN is a potential non-invasive biomarker of oral mucositis whereas the importance of high serum OPN warrants further studies.