TNFAIP3 and mediastinal malignant lymphoma: A20 can be inactivated by promoter methylation, somatic mutations and genomic deletions in various numbers of lymphomas such as marginal zone lymphomas, MALT lymphoma, primary mediastinal B cell lymphomas (PMBLs) and Hodgkin’s lymphoma (Honma et al., 2008; Compagno et al., 2009; Kato et al., 2009; Novak et al., 2009; Chanudet et al., 2010) and the loss of A20 protein due to bi-allelic mutations of TNFAIP3 occurs in some Hodgkin lymphomas and primary mediastinal lymphomas (Schmitz et al., 2009).