In the TCGA study on muscle-invasive UC [7], about 90% of the cancers carried one or more mutations in KDM6A (encoding histone demethylase UTX), KMT2C, KMT2D (encoding histone methyltransferases MLL2 and MLL3), CREBBP, EP300 (histone acetyltransferases), and ARID1A (a SWI/SNF component). The gene discussed is KMT2D; the disease is cancer.