KMT2A (MLL) fusions in aggressive sarcomas in young adults.

KMT2A fusions account for a subset of aggressive unclassifiable sarcomas in young adults. Although it is presently unclear whether these sarcomas belong to a single group, the well-established role of KMT2A fusions as drivers of acute leukaemia and a recent publication regarding identification of YAP1-KMT2A in one unclassifiable sarcoma support the significance of these fusions. Further studies on additional cases are necessary to fully understand the clinicopathological and molecular aspects of KMT2A-rearranged sarcomas.