The highest levels of phosphorylated PAX2 protein were detected in the least invasive cell lines (luminal cell lines MCF-7 and ZR-75-1 [8], Figure 1b), and negatively correlated with protein levels of ERBB2 (Figure 1b), a major player in breast cancer cell invasion and metastasis [5,6,19]: these results support the hypothesis that PAX2 activation in luminal breast cancer cells maintains a mild invasive and metastatic behavior. This evidence concerns the gene PAX2 and breast cancer.