CD53 and cancer: Currently,one of the most promising strategies in cancer treatment is targetedtherapy with cytotoxic conjugates.3−5 The aim of this selectivetherapy is to precisely deliver drugs into the tumor by targetingcancer-specific marker molecules.1,5,45 These include cell surface antigens, growth factorreceptors, cell adhesion molecules, cytokine receptors, Fas/Fas-ligandmolecules, and others.8,46