Background: Head and neck cancer (HNC) is the 6th most common cancer worldwide, with a high mortality rate1. There are currently no routine biomarkers utilized for HNC diagnosis and disease surveillance. Tumour-derived extracellular vesicles (EVs) are actively secreted tumour nanovesicles in biofluids, and have recently emerged as a potential novel biomarker, as they contain high amount of molecular content originating from the primary tumour and can represent the active clonal population2,3.
Aim:
Our study aims to investigate the role of tumour-derived EVs as a novel biomarker in HNC patients undergoing therapy. We aim to: 1) Determine whether fluctuations in the amount of EV in circulation and DNA contained in tumour-derived EV correlates with treatment response; 2) Confirm if DNA tumour mutational burden is predictive of immunotherapy response and 3) Determine whether the baseline immunoprofile of EV-derived RNA reflects the tumour tissue profile and is predictive of response.
Method: Forty-one locally advanced base of tongue (n=31), and recurrent HNC (n=10) patients were consented between 2016-2018 from Sir Charles Gairdner Hospital. Serial blood samples were collected prior to and during treatment, and archived formalin fixed paraffin-embedded (FFPE) tumour samples were recalled for analysis. Tumour-derived EVs is isolated through ultracentrifugation, size exclusion chromatography and precipitation. Extracted EV-derived DNA and proteins will be correlated with clinicopathological features and patient outcome. DNA mutational profiling using targeted sequencing platform will be performed on primary tumoural DNA and tumour-derived EV DNA, and mutation burden will be correlated with response to therapy. Immune profiling of tumoural and EV-derived RNA will be performed using Nanostring technology to characterise the nature of the immune response.
Conclusion:
The project investigates the role of EVs as a novel biomarker in HNC patients, and has the potential to change the way we diagnose and monitor disease response through routine blood tests.