Salivary proteins from dysplastic leukoplakia and oral squamous cell carcinoma and their potential for early detection.

Dysplastic leukoplakia (LP) of the oral cavity is a potentially malignant condition for oral squamous cell carcinoma (OSCC), early detection of which remains an unmet clinical need. In an effort to develop non-invasive biomarker based method for early detection of the disease, differential proteomic profiling was carried out with the saliva from patients with risk habits and diagnosed with LP and those with lymph node negative and positive OSCC in comparison to healthy controls with risk habits. Ninety three proteins were observed at elevated level (≥1.5 fold), and 30 were prioritized based on a scoring system comprising of confidence of identification, presence in the various specimen groups, functional relevance, and their secretory potential. Verification was carried out in independent patient cohorts for 8 selected, representative, upregulated proteins using ELISA. Three of them CD44, S100A7, and S100P were significantly altered in patients with LP as well as OSCC and can be regarded as a panel of biomarker candidates for early detection of the malignancy. Other members may also be investigated in a targeted manner to expand the portfolio of biomarkers for early detection. The mass spectrometry data are available via ProteomeXchange with identifier PXD015722. SIGNIFICANCE: There is an unmet clinical need for non-invasive, biomarker based methods for the improved early detection and the subsequent management of oral cancer. The study represents differential proteome profiling of the saliva of patients with oral dysplastic leukoplakia (LP) - a potentially malignant lesion, patients diagnosed with oral squamous cell carcinoma (OSCC), and healthy controls to identify potential markers for the purpose of early detection of malignancy. From among the matched and prioritized proteins with elevated levels in the saliva of patients with LP and those with OSCC, eight were verified. Three of them - CD44, S100A7 and S100P appeared promising candidates as biomarkers for early detection of the neoplastic predisposition and may form the basis of clinical assays for this purpose.