CUHK Research: Changing the world

From clinic to lab Professor Jun Yu joined CUHK in 1999 as a post-doctoral research fellow of Professor Joseph Sung Jao -y i u , t he renowned r e s e a r che r i n g a s t r oen t e r o l og y a nd hepatology who later became CUHK’s Vice- Chancellor, after practicing medicine at Peking University’s Hospital. “When I was working as a gastrointestinal specialist in Beijing, patients coming to see me were all in the late stages of cancer for which there was really no cure,” Professor Yu recalls. “As a young doctor, I felt so helpless. I wondered: Why can’t we detect these cancers early so that timely intervention is possible?” Colonoscopy is one of the most sensitive tests available for colon cancer screening and investigation. “However, because it is invasive, costly and labour intensive, it is hard to apply it for screening with the large population of China,” she says. “I realised that the only way to make a different kind of clinical breakthrough was to do basic research to find out the cause of cancer.” She began studying the molecular mechanism that causes gastrointestinal cancers, as well as molecular alterations. Very “basic” research At the time Professor Yu started research at CUHK, there was no molecular non-invasive diagnostic test for colorectal cancer. A key discovery by Professor Yu and her team was that the microRNA-92 molecule present in stool is a reliable molecular biomarker for early diagnosis of colorectal cancer based on genomic and metagenomic analysis. Their fecal miR-92a diagnostic kit is the first molecular biomarker approved by the China Food and Drug Administration (now the National Medical Products Administration, or NMPA) for colorectal cancer early diagnosis in 2018. From initial research to producing a test kit approved for nationwide application took over 15 years. At the start, Professor Yu and her students found themselves conducting the most “basic” of basic research — probing large piles of stool collected from patients to identify malignant cells shed from the thin outer layers of tissue lining their gut. “We washed the stool, removed food residues 34