In addition to regulating cellular functions associated with zinc transport, ZIP9 was first identified as a mAR in Atlantic croaker fish ovarian follicle cells [103] and then immediately afterwards in the triple-negative human breast cancer cell lines MDA-MB-468 and MDA-MB-231 as well as in the PC-3 prostate cancer cell line, all of which were stably transfected with ZIP9 [104]. This evidence concerns the gene SLC39A9 and breast cancer.