MEF2B and mantle cell lymphoma: MEF2B is the target of heterozygous somatic non-synonymous and indel mutations in 8 to 18% of diffuse large B-cell lymphoma (DLBCL) [143–146], 13% of follicular lymphoma (FL) [143] and 3 to 7% of mantle cell lymphoma (MCL) [147,148].