Evidence for a pro-metastatic role for PTP1B has centered on PTP1B’s ability to promote Src kinase activity79, 80, and PTP1B has previously been reported to promote, rather than suppress, invadopodium formation in breast cancer cells after being released from the ER membrane by calpain cleavage81, 82. The gene discussed is PTPN1; the disease is breast carcinoma.