In the 1960s, researchers in England noticed an anomaly when investigating chromosomes from surgically removed human tumors. Distinct from the intact chromosomes visible underneath the microscope were numerous “very small double chromatin bodies,” which are today better known as extrachromosomal DNA. Thanks to modern sequencing and imaging techniques, researchers now know that these tiny bits of circular DNA play a big role in cancer outcomes. In this episode, Niki Spahich from The Scientist spoke with Lukas Chavez, an assistant professor in the Cancer Genome and Epigenetics Program at the Sanford Burnham Prebys Medical Discovery Institute, to learn more about his team’s multiomic exploration of extrachromosomal DNA and how it influences medulloblastoma progression and treatment.   Welcome to The Scientist Speaks, a podcast produced by The Scientist’s Creative Services Team. Our podcast is by scientists and for scientists. Once a month, we bring you the stories behind newsworthy molecular biology research. This episode is brought to you by biomodal.