CD40 and neoplasm: Hypermutations were found in low-gradelymphomas throughout CDR1- CDR3 suggestive of positive selection through their antigen receptor.Different VH families were used and more than 69% of tumor immunoglobulins bound different mucosal antigens.CD40L expression was found in the tumor marginal zone in substantial amounts.The in vitro proliferation response of all low-grade MALT-type lymphomas was dependent onanti-CD40- mediated signals and cytokines.