SIRPA and cancer: Increased cell surface heterophilic carbohydrate antigen expression can be targeted by macrophages, such as Thomsen‐Friedenreich antigen (Galß1‐3GalNAcα‐), a common feature in malignant and pre‐malignant epithelia.27 Hence, it is likely that CD47‐SIRPα signaling may also override the activating signals delivered to macrophages by cancer antigens.