In conclusion, our data point out for the first time that oncoproteins of high-risk HPV and EBV cooperate to stimulate cell proliferation and deregulate cell cycle progression of human breast cancer and normal cells; more significantly, this crosstalk can enhance cell motility and invasion abilities of human breast cancer cells via β-catenin and Erk1/Erk2 signaling pathways. Here, MAPK3 is linked to breast carcinoma.