Think for a moment about a young girl, four years old, diagnosed with acute lymphoblastic leukaemia (ALL). This is not so unusual, and in fact, ALL is the most commonly diagnosed childhood cancer. However, only two years earlier, this young girl was also diagnosed with a grade II glioma in her brain, treated by surgical resection with no chemotherapy or radiation exposure. Moreover, her father and her father’s brother both recently died of aggressive glioblastoma multiforme (GBM) brain tumours. This young girl and her family have Li-Fraumeni Syndrome, an inherited defect in one of the TP53 genes leading to a nearly 100% lifetime risk of cancer1.