CDA and acute lymphoblastic leukemia: Interestingly, a subset of cell lines lacking CDA expression, including SEM (a human acute lymphoblastic leukemia cell line) and Raji (a human B lymphoblastoid cell line), was strongly inhibited by either or both oxidized methylcytidines (Fig. 1A and Table S1), suggesting the presence of CDA-independent metabolic pathway(s) directing the cytotoxicity of 5hmdC and 5fdC.