In contrast, our group and others recently identified unexpected critical tumor-supportive functions of the RNF40/H2Bub1-axis in specific cancer types such as mixed-lineage leukemia (MLL) [27], ER+-BC [23], HER2+-BC [27], colorectal [24, 25] and prostate cancer [52]. The gene discussed is KMT2A; the disease is neoplasm.