In the IHC, breast tumor cells were negative for ER, PR, HER2/ neu, GATA3, GCDFP15 and CK20, but positive for CK7, CK19, and CDx2.<h4>Conclusion</h4>The diagnosis of breast metastasis of gastric carcinoma was confirmed according to the past history of patient, histological finding, and immune-histological markers. The gene discussed is GATA3; the disease is breast neoplasm.