NR4A1 and Ureteral obstruction: Although the Nr4a1+ monocyte/macrophage subsets have been identified in colon cancer as a monocyte subtype,[40] in atherosclerotic aorta with antiatherogenic function,[41] in hepatocellular carcinoma as myeloid‐derived suppressor cells (MDSCs),[42] in normal mouse kidneys,[13] and in ureteric obstruction as patrolling monocytes,[43] the role and mechanisms that regulate the Nr4a1/Ear2‐expressing macrophages remain largely unclear.