Our observations might indicate that the in vivo signaling and other effects caused by constitutive activation of CARD11/BCL10/MALT1 (CBM) signaling differ between B and T cells, although the CARD11 mutation is frequently observed in both B-cell malignancies, as the DLBCL ABC type, and in T-cell malignancies, as ATL. Here, MALT1 is linked to diffuse large B-cell lymphoma.