Finding the right treatment for a specific subset of acute lymphoblastic leukemia (ALL) requires a correct diagnosis, but there are many challenges that clinicians face when trying to implement precision medicine. ALL subsets are not as easily identified in comparison to other leukemias, as the various genetic changes that occur in ALL, such as chromosomal rearrangements, deletions of DNA and sequence changes, are challenging to identify. Charles Mullighan, MBBS (Hons), MSc, MD, explains how the team at St. Jude Childrens Research Hospital, Memphis, TN has taken a different approach to diagnosing new ALL patients. Recorded at the 2018 European School of Hematology (ESH) Clinical Updates on Acute Leukemias, held in Budapest, Hungary.