IRF4 and marginal zone lymphoma: Studies have confirmed that compared to MZL, HT-MZL is characterized by elevated serum lactate dehydrogenase levels; upregulated expression of BCL-6, MUM-1, C-MYC, and Ki-67; more frequent mutations in TBL1XR1, CCND3, and ID3; and more common bone marrow involvement (82).