ChEBI: Busulfan is a methanesulfonate ester that is butane-1,4-diol in which the hydrogens of the hydroxy groups are replaced by methanesulfonyl groups. An alkylating antineoplastic agent, it is used for the treatment of chronic myeloid leukemia (although it has been largely replaced by newer drugs). It is also used as an insect sterilant. It has a role as an insect sterilant, an antineoplastic agent, a teratogenic agent, a carcinogenic agent and an alkylating agent. It derives from a butane-1,4-diol.NCI Thesaurus (NCIt): Busulfan is a synthetic derivative of dimethane-sulfonate with antineoplastic and cytotoxic properties. Although its mechanism of action is not fully understood, busulfan appears to act through the alkylation of DNA. Following systemic absorption of busulfan, carbonium ions are formed, resulting in DNA alkylation and DNA breaks and inhibition of DNA replication and RNA transcription. (NCI04)