ANXA2, highly expressed in invasive breast cancer cells, is closely related with poor prognosis, and acts as a molecular switch to EGFR activation. ANXA2 expression is inversely correlated with cell sensitivity to gefitinib. Knockdown of ANXA2 expression in MDA-MB-231 cells increased the gefitinib induced cell death. When ANXA2 was overexpressed in MCF7 cells, the gefitinib induced cell death was decreased. Furthermore, the phosphorylation of ANXA2 at Tyr23 is negatively correlated with the sensitivity of TNBC to gefitinib.