Bulletin No. 1, 2023

As early NPC is relatively asymptomatic, approximately 80% of unscreened patients are diagnosed with advanced NPC, which is more difficult to treat than during the early stages. NPC is closely associated with infection by the EBV. The presence of plasma EBV DNA consisting of short DNA fragments released by NPC cells will help identify asymptomatic NPC patients. Current applications of circulating cancer DNA analysis focus on guiding treatment options and monitoring responses to them. But there has been little information on whether a small asymptomatic tumour could be detected through analysis of circulating DNA. “Our large-scale clinical trial shows for the first time that plasma DNA analysis is useful for detecting early asymptomatic NPC. Even small tumours can release enough tumour DNA to allow sensitive detection of very early cancers,” says Professor Chan, chair professor of chemical pathology. With this technology, 70% of NPC patients can be identified at stages 1 and 2, when there is a much greater likelihood of successful treatment, with a survival rate 10 times higher. In 2017, the landmark findings were published in the New England Journal of Medicine. The study has laid the foundations for using liquid biopsy to screen for other types of cancer. Professor Lo adds, “I co-founded Take2 Health to offer an NPC screening service in Hong Kong.” He is also the scientific co- founder of Grail, which has started offering a detection test for 50 cancers, known as Galleri, that is available in the UK and US. Time magazine listed Galleri as one of the best inventions in 2022. Envisioning a healthier future 25