NSD2 (MMSET/WHSC1)

Class

Small molecule (NSD2 histone methyltransferase inhibitor)

Pathway

Blocks NSD2-mediated H3K36 dimethylation, disrupting the oncogenic epigenetic program driven by the t(4;14) IGH-NSD2 translocation in multiple myeloma

NSD2 (also known as MMSET or WHSC1) is an enzyme that chemically modifies histones, the proteins around which DNA is packaged. Specifically, it adds two methyl groups to a particular site on histone H3 (a mark called H3K36 dimethylation), which influences how tightly DNA is wound and which genes are accessible for transcription. In a subset of multiple myeloma, a chromosomal rearrangement—the t(4;14) translocation—places the NSD2 gene next to a highly active immune-gene enhancer, causing NSD2 to be produced in excess. This drives widespread, abnormal H3K36 methylation across the genome, altering chromatin structure in ways that favor a cancer-promoting pattern of gene expression, including genes that support cell proliferation and survival. Small-molecule inhibitors that block the catalytic activity of NSD2 aim to reverse this abnormal chromatin state and shut down the oncogenic transcriptional program that depends on it. Because this translocation is a defining and consistent feature of a molecularly distinct subgroup of multiple myeloma, NSD2 inhibition represents a targeted epigenetic strategy directed at the root cause of that subtype's disease biology, rather than at a downstream or generic proliferative signal.