In this regard, opposite functions of KDM6B and KDM6A have been demonstrated in the T-cell acute lymphoblastic leukaemia (T-ALL) [168], being KDM6B essential to initiate and maintain these tumors, whereas KDM6A acts as a tumour suppressor, being frequently genetically inactivated. The gene discussed is KDM6B; the disease is acute lymphoblastic leukemia.