Immunohistochemical Analysis of Expression of GATA3 in Carcinoma Breast and its Correlation with Prognostic Parameters

Abstract

Background: GATA3 plays an essential role in the normal development and function of the mammary gland where it promotes the luminal transcriptional program. Its loss is implicated in the pathogenesis of breast cancer. We proposed to study the expression of GATA3 in carcinoma breast by immunohistochemistry and determine its correlation with prognostic parameters.
 Methods: The expression pattern of GATA3 was evaluated by immunohistochemistry in 30 cases of invasive breast carcinoma. GATA3 scoring was done and a score of ≥ 1+ was considered positive. Patient characteristics, including age, tumour laterality, tumour size, lymph node status, tumour grade, histological type, molecular subtypes were collected. The relationships between protein expression and clinicopathological variables were analysed. Statistical significance was determined by Pearson’s chi-square test and Mann Whitney U test (for age).
 Result: 46.7% of cases (14/30) scored positive for GATA3 expression in tumour cells including 63% of luminal subtypes, 14% of Her-2 neu enriched carcinomas and 20% of triple negative carcinomas. Most positive cases (35.7%) demonstrated 3+ staining. GATA3 expression showed an inverse association with histological grade (P = 0.012) and HER-2 overexpression (P = 0.038), and a direct association with ER expression (P =0.017) and PR expression (P =0.009).
 Conclusion: GATA3 is luminal marker as it shows strong association with ER and PR in breast cancers. High GATA3 expression is also correlated good prognostic parameters like low tumour grade. Our findings advocate for GATA3 as a promising new breast-specific immunomarker.