As all three factors in humans are implicated in neurodevelopment49,50,56 and cancer24,51,52, and HCF-1’s function in cancer has already been linked to the regulation of mitochondrial gene expression39, understanding how MLL5, HCF-1, and HDAC1/2 interact and the pathways they regulate in humans could have broad implications for understanding both aging and human disease. The gene discussed is HDAC1; the disease is cancer.