DNMT1 and neoplasm: It is unclear whether the clinical activity of 5-azaC requires demethylation of candidate tumour-suppressor genes; whether the anticancer effect is a result of activities independent of dna methylation, mediated through 5-azaC binding of dnmt1 and other dnmts; or whether the main activity of this agent relates to its non-specific toxicity as a nucleoside analogue.