Association Between GATA3 and Histopathological and Immunohistochemical Parameters in Early-Infiltrating Breast Carcinomas.

Objective: This study evaluated the frequency of GATA-binding protein 3 (GATA3) expression in early breast cancer and its relationship with histopathological and immunohistochemical parameters.

Materials and methods: GATA3 was analysed by immunohistochemistry in histological sections of tumors from 105 female patients, with histological diagnosis of invasive breast carcinoma (BC), at clinical stages I, II and IIIA, who underwent primary surgical treatment. GATA3 nuclear expression was determined as the percentage of positive tumor cells and further categorized as high (positive expression in more than 95% of cells) or non-high (negative or low positive expression in up to 95% of tumor cells). GATA3 expression was analysed according to the patient age, tumor and node pathological stage, histological type, histological and nuclear grade, lymphovascular invasion, and estrogen receptor (ER), progesterone receptor (PR), androgen receptor (AR), human epidermal growth factor 2 (HER2) status, and Ki-67 expression.

Results: GATA3 expression was positive in 103 cases (98.1%). High expression was significantly associated with low histological and nuclear grade, positive hormonal receptors, and less proliferative activity based on Ki-67 expression. A prominent feature was that 94.7% of the ER-positive/HER2-negative cases presented high-GATA3 expression, as 94.0% of the tumors showing high-GATA3 were ER-positive. In ER-negative/HER2-positive or ER-negative/HER2- negative, high-GATA3 was present in 25% while 75% were non-high-GATA3 compared with ER-positive/HER2- negative (4.1%) and ER-positive/HER2-positive (20%). Proliferative activity in triple-negative breast cancer tended to be higher among tumors with low-GATA3, irrespective of AR expression. In the group of ER-positive/HER2-negative tumors only three cases were low-GATA3 (85% and 80%), both with high proliferative activity.

Conclusion: High GATA3 expression is associated with favorable histopathologic and immunohistochemical BC prognostic factors.