CD55 and neoplasm: The upregulation of complement inhibitor factors (CD55, CD59 and CD46) is one of several strategies adopted by tumor cells to evade the immune system.25, 26 A number of secondary functions for complement regulatory proteins has been identified, including cell adhesion and being mediators of regulatory T cells.27 The mechanisms that result in their production and their role in the pathogenesis of tumors remain to be defined, although their overexpression potentially makes them a good therapeutic target.