Although further tests with primary tumor tissues are required, the unexpected correlation between ER status and Src/PTP alpha dependence in breast cancer cell lines may be important for planning therapeutic strategies, and the insensitivity of normal breast cells to the RNAi highlights the potential of PTP alpha, which may be easier to target than Src, as a therapeutic target in ER-negative breast cancer.
Our results are the first to suggest that PTP gamma is a potential estrogen-regulated tumor suppressor gene in human breast cancer which may play an important role in neoplastic processes of human breast epithelium.
The findings that protein tyrosine phosphatases (PTPs) regulate cell proliferation, response to growth factors, and cellular adhesion and the discovery that mutations in PTP genes are associated with breast cancer suggest that altered expression of PTPs contributes to the breast cancer cell phenotype.