SIRPA and acute myeloid leukemia: A blockade of CD47 by therapeutic monoclonal antibodies disruptsCD47-SIRPα interaction and leads to phagocytosis in AML andsolid tumors.1,3,4 Uponthe blockade of CD47, tumor cells are shown to display a pro-phagocyticsignal on their surfaces to be phagocytosed.5 Calreticulin (CRT) is a chaperone protein located in the endoplasmicreticulum (ER).