Tumor necrosis factor receptor (TNFR) in chondrocytes, sortilin in breast cancer cells, cation-independent mannose 6-phosphate receptor in neuroblastoma cells, and EphA2 in human umbilical vein endothelial cells and bladder cancer cells also bind extracellular progranulin [21, 22, 24, 25, 26]. The gene discussed is SORT1; the disease is breast cancer.