Together, our findings with polyamine uptake and cytotoxicity assays indicate that overexpressing ATP13A4 WT in MCF10A cells confers a polyamine uptake phenotype resembling MCF7 cells with high endogenous ATP13A4 expression, indicating that ATP13A4 is the driver of the increased PTS in MCF7 breast cancer cells. This evidence concerns the gene ATP13A4 and breast cancer.