Given the potential clinical application of DOT1L inhibitors in cancer treatment, we next tested the effects of combinatorial treatment with standard of care therapies for colorectal cancer, where 5-fluorouracil (5-FU), a nucleoside analogue, is frequently combined with the clinically utilized topoisomerase I inhibitor irinotecan (IRI) in a combination referred to as FOLFIRI [29, 30]. The gene discussed is DOT1L; the disease is colorectal cancer.