AICDA and MALT lymphoma: AID is consistently expressed not only in neoplastic cells in Hodgkin's lymphoma but also in many other human hematological malignancies including CLL (123–125), B-cell acute lymphoblastic leukemia (126), mantle-cell lymphoma (127), and in some cases of MALT lymphoma, which derives from marginal zone B cells in mucosa-associated lymphoid tissue, of immunocytoma, which is derived from plasma cells (117, 119), and of hairy cell leukemia, which derives from memory cells (128).