PDZK1 and esophageal cancer: PDZK1 was originally found in the apical brush border membrane of the proximal tubules of the kidney [15], and in recent years, it has also been found to play a role in high-density lipoprotein transport, esophageal cancer, renal cell carcinoma, small intestine, estrogen-related pigmentation, and ER( +) breast cancer [16–20].