Research progress on Zn transporter family SLC39A/ZIP and tumors

As an essential trace element for human, Zn is involved in the synthesis of various enzymes, and plays important roles in the growth and proliferation of cells. At the cellular level, Zn2+ homeostasis is maintained through the complex mechanisms of uptake, storage and excretion, where the Zn transporter families play certain roles. Two major Zn transporter families, namely the SLC30 (ZnT) family and the SLC39 (ZIP) family, have been identified, which act to control the intra- and extracellular equilibrium of Zn2+ . While the ZnT fa-mily mainly transports Zn out of the cells, while the ZIP family mainly contributes to the uptake and transport of Zn into the cells. The ZIP family has been noted to be associated with various diseases, and be closely related to the development and progression of tumors. Recent studies have suggested low ZIP1 and ZIP2 expression in prostate cancer, high ZIP6, ZIP7 and ZIP10 expression in breast cancer, high ZIP3 and ZIP4 expression in pancreatic cancer, and high ZIP5 and ZIP6 expression in esophageal cancer. The ZIP family may, therefore, function as tumor suppressor genes in prostate cancer, and oncogenes in pancreatic cancer, breast cancer and esophageal cancer. This paper reviews the latest research progress on SLC39 transporter family and tumors. Key words: Zinc; Zinc transporter; Cancer