ince chemotherapy was first used to treat cancer in the 1940s, tumours have been tackled according to their organ or tissue of origin. Drugs used for breast-cancer therapy, for example, might be different from those used for lung or colorectal cancers.In the past few years, however, clinicians have begun to use a new approach. Cancer is now being defined and treated in a more personalized and precise way -tumour genomes are sequenced so that people receive drugs matched to the genetic profile of their cancer cells. In 2017, the US Food and Drug Administration (FDA) approved the first tissue-agnostic drug for cancer -a treatment effective against tumours with a specific genetic alteration, regardless of the cancer's location. Two more tissue-agnostic drugs followed, in 2018 and 2019. "It's changing all of oncology," says Razelle