Background

Triple Negative (TN) breast cancer is an aggressive subtype of breast cancer defined as the absence of Her2 gene amplification and/or expression, absence of ER expression, and absence of PR expression. In contrast to the other two major subtypes, the molecular mechanism underlying TN is poorly understood and no effective treatment for the TN patients currently exists. In the search for molecular targets, Sun et al (1) recently published identification of PTPN12 tyrosine phosphatase protein as a potential target for TN patients by performing a genetic screen for kinase and phosphatase molecules in Human Mammary Epithelial cells. This study suggested that PTPN12 acts as a tumor suppressor and its loss of function/expression promotes cell proliferation partly through hyperactivation of HER-signaling pathways.

In order to gain further insight into the molecular mechanism of PTPN12 and its relevance to TN breast cancer cases, we performed gene expression analysis of the 105 TN patients.