Studies have shown that GATA3 has a diagnostic sensitivity of 32–90%, is localized in the nucleus, and is positive in all breast tumor cells, whereas GCDFP-15 is positive in only a subset of tumor cells, and GATA3 expression is extremely low in gastrointestinal cancers, so the identification of breast cancer gastric metastases with GATA3 antibody would be very effective [17]. The gene discussed is GATA3; the disease is breast neoplasm.