Moreover, EGF, one of the most potent mitogens that transmits signals for cell growth, survival, and motility by binding and activating EGFR43–45, induced an increase in h-ras, k-ras, p-Erk1/2, p-GSK3β, β-catenin, Snail, c-Myc, cyclin D1, and N-cadherin, and a decrease in E-cadherin in SHP-1-overexpressing breast cancer cells, thereby reversing the changes caused by SHP-1. This evidence concerns the gene MAPK3 and breast cancer.