A second-generation, mixed-backbone, phosphorothioate antisense oligonucleotide (ODN) with potential antitumor activity. MG 98 is a highly specific inhibitor of translation of the mRNA for human DNA (cytosine-5-)-methyltransferase 1 (DNMT1), hybridizing to the 3' un-translated region of DNMT1 mRNA. The silencing of DNMT1 translation by MG 98 may result in the prevention or reversal of abnormal methylation of tumor suppressor genes and ultimately in tumor growth inhibition or tumor regression. or A substance being studied in the treatment of cancer. It blocks the production of a protein called DNA methyltransferase, which helps control gene expression. This may kill cancer cells that need DNA methyltransferase to grow. It is a type of antisense oligonucleotide.