My group first reported the presence of cell-free fetal DNA in maternal plasma in 1997. Since then, we have elucidated the basic biological parameters governing this phenomenon. We have also translated this discovery into a platform for non-invasive prenatal testing (NIPT) that is used globally. We have also applied a similar principle to develop blood-based DNA tests for detecting cancer. This work has led to the commercialisation of the first multi-cancer, early detection (MCED) test. I shall share some of my experiences from this journey during this lecture.