Targeted Mass Spectrometry-Based, Prospective Verification of Protein Biomarkers in Dry Saliva Spots for Monitoring the Recurrence of Oral Cancer and Malignant Transformation of Oral Precancer Lesions

Oral cancer, one of the malignant diseases with high prevalence, has become a growing burden of health care system worldwide. Oral squamous cell carcinoma (OSCC) accounts for more than 90% of oral cancer cases. Most cases of OSCC develop from visible lesions of oral potentially malignant disorder (OPMDs) that are seen in the oral cavity and display oral epithelial dysplasia. Although visual inspection of oral mucosa and pathological examination of dysplasia tissue biopsies facilitated the detection of OSCC, more than 50% of oral cancer patients in Taiwan have presented themselves with late-stage tumors (stage III or stage IV). Many candidate biomarkers for oral cancer have been discovered in the past decades; however, very few of them have been verified and translated into clinical use. Importantly, there are no biomarkers currently approved by official health agents in the endemic areas for aiding OSCC management. We previously identified a four-protein marker panel that was selected to effectively distinguish oral cancer patients from non-cancer groups (PNAS USA, 2016;113(41):11549-11554). These previous results were established by using saliva samples of a retrospective cohort via cross-sectional collection. To verify the utility of the four-proteins marker panel for predicting recurrence of OSCC or malignant-transform from OPMD to OSCC, we plan to continue collecting saliva samples longitudinally from subjects (50 OPMD cases and 50 OSCC cases) during regular follow-up every 3-6 months, at least 3 years period, for a further prospective study. Otherwise, we also plan to introduce dry spot sampling method into the standardized protocol of saliva collection providing a more convenient and limitless storage type for large sample-size collection. The specific aims of this proposal are: 1. Establishment of the best practice of dry saliva spot (DSS) sampling for clinical use, including evaluation of (1) the pre-analytic variation caused by sample collection/preparation and storage of using DSS in clinic, and (2) the accuracy and precision of using DSS as study material for absolute protein quantification by targeted mass spectrometry approach. 2. Using prospectively collected saliva specimens to further verify the clinical utility of the four-protein marker panel (identified in our previous study) by targeted mass spectrometry for predicting recurrence of OSCC or malignant-transform from OPMD to OSCC. Meanwhile, the verification results obtained from using frozen saliva and dry saliva spot will be compared. 3. Quantitative analysis of the proteome alteration in the longitudinally collected saliva samples from the subjects who show recurrence of OSCC or malignant transformation from OPMD to OSCC. The goal was to (1) understand the long-term changes of salivary proteins alone with time line of transformation from OPMD to OSCC or recurrence of OSCC, and (2) discover salivary proteins that show dysregulation before tumor occurrence.

Project ID:PC10901-0194
External Project ID:MOST107-2320-B182-027-MY3