Given that the interruption of the MZF-1/Elk-1 interaction significantly affected EMT, we examined the efficacy of MZF-160–72 and Elk-1145–157 peptides against breast cancer cells by using cell-permeable peptides fused to a short sequence (residues 48–57) of the HIV trans-activating regulatory protein (TAT) [31]. This evidence concerns the gene ELK1 and breast cancer.