GATA3 and Endometrial Intraepithelial Neoplasia: Endometrioid adenocarcinoma is characterized by squamous, mucinous, or ciliated differentiation and presence of precursor lesion (endometrial intraepithelial neoplasia/atypical hyperplasia), and expression of ER and PR but it is negative for GATA-3 immunohistochemically.