Although LSD1 is highly upregulated and required for the GC reaction and repression of KMT2D target genes, its methyltransferase function is not required for this effect.102 Of the four KDM5 genes, KDM5C and to a lesser extent KDM5A are highly expressed in GC B cells, FL, and DLBCL. Here, KMT2D is linked to diffuse large B-cell lymphoma.