Halting triple negative breast cancer by targeting PROCR

Cancer stem cells (CSCs) achieved prominence as a concept to explain the inexorable growth of cancers, but the paucity of robust CSC markers for solid tumors has seen the field wane in recent years. Wang et al. now report that a cell surface protein PROCR (Protein C Receptor) enriches for CSCs in about half of triple negative breast cancers and show that inhibition of receptor function by a nanobody profoundly decreases tumor growth, thus highlighting PROCR as a potential therapeutic target.