Genes involved in transport such as ATOX1, a copper chaperone protein that functions as an antioxidant and is involved in breast cancer cell migration41,42 and FXYD2, a sodium/potassium-transporting ATPase subunit whose increased expression in tumors may contribute to angiogenesis43, were hypomethylated in TN-DCIS and invasive breast cancer. This evidence concerns the gene FXYD2 and breast cancer.