GATA3 and lung adenocarcinoma: Adenocarcinoma of the lung and ductal carcinoma of the breast, which can be differentiated by IHC staining with antibodies of thyroid transcription factor-1 (TTF-1; 75% sensitivity and specificity) (38, 39) and GATA binding protein 3 (GATA-3; over 90% sensitivity and specificity), respectively (38, 40, 41).