Comparative analysis of whole saliva proteomes for the screening of biomarkers for oral lichen planus

Objective To screen possible biomarkers in whole saliva from oral lichen planus (OLP) patients by proteomic techniques. Methods Two-dimensional electrophoresis and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry were applied to whole saliva of OLP patients and controls, and the differential protein components were analyzed with peptide mass fingerprinting and database searching. Results A total of 31 protein spots representing 14 proteins with at least two-fold difference in abundance between OLP and controls were identified. Among these, the expression of urinary prokallikrein was increased while short palate, lung and nasal epithelium carcinoma associated protein (PLUNC) was decreased in all samples of OLP. Conclusions Urinary prokallikrein and PLUNC may be the new biomarkers which play a role in inflammation and immune response of OLP. Received 22 September 2005; returned for revision 16 January 2006; accepted by A. Falus 19 April 2006