Bulletin No. 1, 2023

in prenatal testing globally. Circulating DNA blood testing can also be applied to cancer screening. In 2017, Professor Lo’s team demonstrated that plasma Epstein-Barr virus (EBV) DNA analysis is useful in screening for asymptomatic nasopharyngeal carcinoma (NPC). The leading scientists behind these milestones, professors Dennis Lo, Rossa Chiu and Allen Chan, have come together to establish the Centre for Novostics at InnoHK. The name stands for “novel diagnostics”, which means that the centre aims to innovate in molecular diagnostics, particularly prenatal testing and cancer diagnostics. Professor Lo co-founded Xcelom in 2014 to commercialise the test. The name comes from the term “extracellular genome”, which means genomic DNA swimming outside the blood cells are measured. Since its introduction to clinical practice in 2011, NIPT has been widely adopted globally and helped millions of expectant mothers every year. “The blood test can be done as early as week 10 of pregnancy, whereas an amniocentesis has to be performed no earlier than week 16,” Professor Lo explains. Studies have shown that safeT21 is more accurate compared with the traditional Down Syndrome screening test, resulting in an almost 30% reduction in the number of invasive procedures such as amniocentesis and chorionic villus sampling performed in Hong Kong. Life-saving cancer screening Just as a growing foetus sheds cell-free DNA into maternal blood, so tumours do the same to their host’s blood. A 20,000-person study led by Professor Lo and Professor Allan Chan revealed that NPC, a common cancer in Hong Kong and southern China, can be detected among asymptomatic people with the help of a plasma EBV DNA test. A paradigm shift in prenatal testing “As foetal DNA fragments exist randomly outside blood cells, it’s difficult to count chromosomes with conventional methods to find trisomy 21, an additional chromosome leading to Down syndrome,” says Professor Lo. Eventually, he identified the ratio of chromosomes via massive parallel sequencing to efficiently use the information stored in plasma DNA. The accuracy is over 99%. The technology has since been translated into safeT21. (Source: Centre for Novostics) 24 Chinese University Bulletin No. 1, 2023