In our cases, cytokeratin 7, TTF-1, p63, and p40 for lung tumors; CK7, GATA3, and GCDFP-15 for breast tumors; and cytokeratins, synaptophysin, chromogranin, and CD56 for neuroendocrine tumors were the most used markers. The gene discussed is GATA3; the disease is breast neoplasm.