CUHK Research: Changing the world

small to be translated into clinical medical diagnosis,” recalls Professor Lo. He returned to join CUHK in 1997, determined to make a breakthrough. “I came across two articles about cancer patients carrying cancer DNA in their plasma or serum, from which I thought – tumours grow in patients’ bodies in a way somewhat similar to foetuses developing in wombs. While many scientists at that time had a general assumption that DNA belonged only within a cell, I took the bold move to propose that foetal markers could also be found in maternal plasma. It turned out to be a correct hypothesis.” Building on the momentum, Professor Lo’s team eventually identified the ratio of chromosomes via massive parallel sequencing to efficiently use the information stored in plasma DNA. They found a way to use critical information stored in plasma DNA to detect the presence of a foetus with Down syndrome to an accuracy higher than 99%. A paradigm shift “Our research created a paradigm shift i n p r e n a t a l med i c i n e ,” P r o f e s s o r Lo acknowledges. Since its introduction to clinical practice in 2011, NIPT has been adopted globally, helping expectant mothers in over 60 countries. “The technology has now become the standard prenatal testing method for Down syndrome, obviating the need for About one in 700 children around the world is diagnosed with Down syndrome, a chromosomal disorder caused by the presence of an extra copy of chromosome 21 in a human embryonic cell, itself associated with delayed physical growth and intellectual disability. Traditionally, expectant mothers opting to take early pregnancy tests to detect whether their children might have Down syndrome bore the risk of miscarriage, as certain tests needed to penetrate the womb near the foetus. That changed after Professor Lo, who is also Associate Dean (Research) of CUHK's Faculty of Medicine, entered the international research scene. “Previous testing methods such as nuchal translucency scan and blood testing did not have high accuracies,” says Professor Lo. “Amniocentesis, another invasive test with relative higher accuracy could cause miscarriages. I was therefore motivated to develop a safe alternative with a high accuracy.” He started working on a solution in 1989, while still a medical student at the University of Oxford. A correct hypothesis Professor Lo’s approach was to search and test for foetal cells in pregnant women’s blood, balancing research while studying for finals. “At first, the research didn’t go very smoothly – the number of foetal cells was too Our research created a paradigm shift in prenatal medicine. The technology has nowbecome the standard prenatal testing method for Down syndrome. 28