Abstract

Tackling Global Health Issues Using a Simple Saliva Test

Chamindie Punyadeera, Associate Professor/Head/Saliva Translational Research Group, Queensland University of Technology

There is increasing evidence linking oral health to systemic diseases. As such, human saliva is gaining momentum as a diagnostic fluid for the future. Saliva is an ideal diagnostic medium due to the ability to collect it non-invasively. We have been investigating the utility of saliva in diagnosing heart failure patients, and have detected cardiac specific NT-proBNP proteins in saliva (76.8 pg/mL), as well as cardiac troponin-I. The common acute phase inflammatory protein, C Reactive Protein, was also detected in saliva from controls (285 pg/mL) and in cardiac patients (1680 pg/mL) (p<0.01). Oral cavity cancers are more prevalent in emergent economies, whereas the incidence of oropharyngeal cancers is rapidly increasing in the western world. About 50% of these patients die within five years of initial diagnosis due to high burden, aggressive disease and intensive treatment. Diagnostics tools for early detection of these head and neck cancers (HNCs) are desperately needed, in order to reduce disease and treatment-related mortality and morbidity. DNA methylation changes are a hall mark of tumorigenesis. In this study, we have measured DNA methylation levels of RASSF1, p16INK4a, TIMP3, PCQAP 5’ and PCQAP 3’ in healthy control and HNC patient saliva. The results obtained with this particular panel indicate a sensitivity of 71% and a specificity of 80% in discriminating healthy controls (n=122) from HNC patients (n=133). A separate panel measuring nine salivary miRNA biomarkers demonstrated a sensitivity of 95% and a specificity of 93% (AUC = 0.98) when discriminating HNC patients (n=100) from pre-cancer patients (n=29). Significant salivary miRNA changes were observed when detecting patients with early stage tumours vs patients with advanced stage tumours, highlighting the potential clinical utility as a screening tool. In addition, we have also developed a non-invasive method to detect human papillomavirus (hpv-16) in salivary oral rinses; with our test showing a sensitivity of 90% and specificity of 100%. The non-invasive and simple, rapid nature of saliva collection, coupled to serial sampling and cost-effectiveness, makes saliva as an attractive biological fluid for both emerging and developed world. Expansion and implementation of saliva testing for cancer and heart failure provides a window of opportunity for earlier interventions and prevention strategies.