ETV4 and breast cancer: The proposed mechanisms of breast tumorigenesis by PEA3 group partly include that they promote breast cancer incidence, progression and invasion through transcriptional activation of several genes, such as HER2, smad7, matrix metalloproteinases (MMPs) and cyclooxygenase (COX)-2 by interaction with the coactivators CBP and p300, and an associated kinase [1,15,16].