CD33 and neoplasm: Furthermore, a trispecific molecule consisting of (1) a single chain variable fragment (scFv) binding to a tumor antigen, (2) the endogenous SIRPα domain to block the CD47-SIRPα signaling pathway and (3) a scFv to trigger recruitment and activation of effector cells may recapitulate the antitumor activity of SIRPα-antiCD33 licMAB and not induce CD33 internalization.