An independent cohort of 51 DLBCL cases (Supplementary Table S2) with (n = 31) and without (n = 20) lymphomatous effusions were immunohistochemically studied to validate the role of MUM4, HDAC1 and MDM2 overexpression in the formation of lymphomatous effusions. This evidence concerns the gene HDAC1 and diffuse large B-cell lymphoma.