NCIt definition : A thiopurine nucleoside derivative with antineoplastic activity. After conversion
to the triphosphate, beta-thioguanine deoxyriboside is incorporated into DNA, resulting
in inhibition of DNA replication. This agent is cytotoxic against leukemia cell lines
and has demonstrated some activity against leukemia cells in vivo. Beta-thioguanine
deoxyriboside demonstrates antineoplastic activity against 6-thioguanine-resistant
tumor cells. (NCI04);