In order to create a gain-of-function cellular model based on the stable overexpression of MT3, we screened the cultured noncancerous (hTERT-HME1) and breast cancer cell lines (MCF-7, SK-BR-3, BT-474, MDA-MB-231 and MDA-MB-231/BO2) for the expression of MT3 mRNA and protein. This evidence concerns the gene MT3 and breast cancer.