PTPN1 and breast carcinoma: In breast cancer cells, high PTP1B expression is associated with Src activation and increased pseudopodia formation; however, inhibiting PTP1B can delay the formation of breast tumors and reduce the risk of breast cancer lung metastasis through the suppression of Src/Ras/ERK and AKT signaling pathways (Julien et al., 2007; Cortesio et al., 2008; Arias-Romero et al., 2009).