Salivary apoptotic microvesicles as biomarkers for prognostic non-healing oral ulcers and oral cancer: a cross-sectional study

Microvesicles (MVs) are membrane vesicles secreted by cells and are present in the saliva of healthy individuals. It has various functions and has been reported to be a biomarker for malignant tumors. The changes in saliva levels of MVs associated with disease(s) is unclear. This study aimed to determine the proportion of salivary apoptotic MVs and their association with oral ulcer(s) in patients with non-healing oral ulcer(s) and reported oral cancer. Saliva (5 mL) was collected from patients with non-healing oral ulcer(s) and reported oral cancer (at the time of saliva collection, the participant have an oral ulcer(s) in the oral cavity and have an oral cancer lesion; n = 73) and healthy volunteers with oral ulcer(s) (n = 62). A standard differential centrifugation protocol was used for the purification of MVs. Dynamic light scattering and transmission electron microscopy were used to characterize MVs. Flow cytometry was used to quantify salivary apoptotic MVs. Immunocytochemistry was performed according to a standard protocol. None of patients with oral cancer has smoking and drinking habit. The majority of saliva samples derived from patients with non-healing oral ulcer(s) and reported oral cancer were more positive for the fluorescent dye carboxyfluorescein succinimidyl ester than those of healthy volunteers with oral ulcer(s). Salivary fluid obtained from patients had membrane-limited vesicles that were round and/or slightly elongated in shape, with diameters of 100-1,000 nm. The number of salivary apoptotic MVs was higher in patients with non-healing oral ulcer(s) than in those derived from healthy volunteers with oral ulcer(s) (p < 0.001). There was an association between salivary apoptotic MVs in patients with non-healing oral ulcer(s) and the degree or severity of oral ulcers (p < 0.001). Levels of salivary apoptotic MVs are elevated in patients with non-healing oral ulcer(s) and confirmed oral cancer. Elevated levels of salivary apoptotic MVs are associated with clinicopathological data of patients with oral cancer. Evidence level: IV. Technical efficacy: stage 3.