PTPN11 and breast cancer: Next, we assessed the relative contribution of the kinase – phosphatase balance in this process by determining the effect of Sara (Src inhibitor) and SHP099 (Shp2 inhibitor) on proliferation of a panel of breast cancer cell lines, including the MM231 cells and another triple-negative breast cancer line, MDA-MB-468 (MM468) (Extended Data Fig. 6a).