We demonstrate that the API2-MALT1 fusion oncoprotein created by the recurrent t(11;18)(q21;q21) in mucosa-associated lymphoid tissue (MALT) lymphoma induces proteolytic cleavage of NF-?B-inducing kinase (NIK) at arginine 325.     ///    Cleavage of NIK by the API2-MALT1 fusion oncoprotein leads to noncanonical NF-kappaB activation.. 