SLC39A6 and breast cancer: Multiple zinc transporters (such as ZnT2, ZIP6/LIV1, ZIP7 and ZIP10), zinc-permeable ion channels (such as TRPC6, TRPM7, and TRPV6), as well as metallothionein were reported to be overexpressed in breast cancer, some of which are associated with breast cancer metastases and poor prognosis (60).