ATF3 is also known as an activator of the tumor invasive potential by up-regulating the expression of the matrix metalloproteinase (MMP) family members (i.e., MMP-1, MMP2, MMP-9 and MMP-13) [70], whose mRNA and protein abundance are correlated with BC invasion and metastasis [71]. This evidence concerns the gene MMP9 and neoplasm.