Discovery and preclinical validation of proteomic biomarkers in saliva for early detection of oral squamous cell carcinomas.

OBJECTIVES: Our aim was to identify and prevalidate a set of salivary proteins that can distinguish oral squamous cell carcinomas (OSCC) patients from healthy individuals and patients with oral potentially malignant disorders (OPMD).

SUBJECTS AND METHODS: Proteomes of 60 saliva samples from healthy individuals, OPMD patients, and OSCC patients were assayed using the isobaric tags for relative and absolute quantitation (iTRAQ) method. Enzyme-linked immunosorbent assay (ELISA) was used to prevalidate the candidate biomarkers in an independent sample set (n = 90).

RESULTS: In total, 246 differentially expressed proteins were identified by comparing each two groups, and 21 proteins were differentially expressed when OSCC was compared with both OPMD and Control. Three proteins, namely, solute carrier family 3 member 2 (SLC3A2), S100 calcium-binding protein A2 (S100A2), and interleukin-1 receptor antagonist protein (IL1RN), were selected as candidate biomarkers. Comparing the OSCC group with the healthy group, the area under curve (AUC) of the three combined biomarkers was 0.89, with a sensitivity of 83.33% and a specificity of 83.33%. Comparing the OSCC group with the OPMD group, the AUC value was 0.87, with a sensitivity of 93.33% and a specificity of 70.00%.

CONCLUSION: Our study indicates that salivary proteomics is promising for the discovery of OSCC biomarkers.