Comparative evaluation of 5-15-kDa salivary proteins from patients with different oral diseases by MALDI-TOF/TOF mass spectrometry.

OBJECTIVES: The present study aimed to determine the potential use of matrix-assisted laser desorption/ionization with time-of-flight/time-of-flight mass spectrometry (MALDI-TOF/TOF MS) for analyzing specific patterns of mass signals of low-molecular-weight proteins in saliva from patients with different oral diseases. MATERIALS AND METHODS: Unstimulated whole saliva samples were collected from healthy subjects (n = 30) and patients with oral diseases including oral cancer (n = 30), oral lichen planus (n = 30), and chronic periodontitis (n = 30). Proteomic profiles of 5,000-15,000-Da salivary proteins were evaluated by MALDI-TOF/TOF MS. Quantification of mass signals was performed by FlexAnalysis and ClinProTool software. RESULTS: In oral cancer, the percentages of mass signals at 5,592.26 and 8,301.46 Da were significantly increased as compared with other groups (p = 0.002 and p = 0.030, respectively). In oral lichen planus, the percentages of mass signals at 12,964.55 and 13,279.08 Da were significantly increased as compared with other groups (p < 0.001, and p < 0.001, respectively). In chronic periodontitis, the percentages of mass signals at 5,835.73 and 9,801.83 Da were significantly decreased as compared with other groups (p = 0.003 and p = 0.005, respectively). CONCLUSIONS: The present study demonstrated a potential use of MALDI-TOF/TOF as a rapid screening method to differentiate one oral disease from others by identifying specific patterns of mass signals in saliva from patients. However, MALDI-TOF/TOF has several limitations regarding the identification of the candidate mass signals. CLINICAL RELEVANCE: MALDI-TOF/TOF MS can be used as a rapid screening method to differentiate one oral disease from others with a caution concerning peptide identity.