A20 is frequently inactivated by deletion, mutation, and/or promoter methylation in several types of lymphomas, such as extranodal marginal zone lymphoma of mucosa-associated lymphoid tissue (MALT lymphoma) [3]–[8], diffuse large B-cell lymphoma (DLBCL) [3], [4], [9], [10], Hodgkin's lymphoma [3], [11], [12], mediastinal large B-cell lymphoma [11], nodal and splenic marginal zone lymphomas [5], [13], follicular lymphoma [3], [4], mantle cell lymphoma [3], [4], Burkitt's lymphoma [4], and AIDS-related lymphoma [14]. This evidence concerns the gene TNFAIP3 and diffuse large B-cell lymphoma.