EXPRESSION OF GATA3 IN INVASIVE DUCTAL CARCINOMA OF THE BREAST: AN IMMUNOHISTOCHEMICAL CLINICOPATHOLOGICAL STUDY

Abstract

Background

GATA-binding protein 3 (GATA3) is a lineage-specific transcription factor that plays a critical role in mammary epithelial differentiation and has emerged as a valuable immunohistochemical marker in breast carcinoma. However, its association with clinicopathological characteristics and molecular subtypes remains variable across different populations. The present study evaluated GATA3 expression and its relationship with histopathological parameters, hormone receptor status, HER2 expression, and immunohistochemically defined molecular subtypes in invasive ductal carcinoma of the breast.

Methods

This cross-sectional study included 52 histopathologically confirmed cases of invasive ductal carcinoma, no special type (IDC-NST), treated at a tertiary care teaching hospital. Formalin-fixed, paraffin-embedded tissue sections were subjected to immunohistochemistry for GATA3, ER, PR, and HER2. GATA3 expression was assessed using a semi-quantitative immunoreactivity scoring system and categorized as negative, weak, moderate, or strong. Associations between GATA3 expression and clinicopathological variables were analyzed using the Chi-square test or Fisher's exact test, with p < 0.05 considered statistically significant.

Results

GATA3 expression was positive in 27 of 52 cases (51.9%). A significant association was observed between GATA3 expression and histological grade (p = 0.008), with higher positivity in Grade II than Grade III tumors. GATA3 expression was also significantly associated with ER positivity (p = 0.032) and PR positivity (p = 0.019). No significant associations were found with patient age (p = 0.721), tumor size (p = 0.300), lymphovascular invasion (p = 0.176), axillary lymph node status (p = 0.673), or HER2 expression (p = 0.278). Analysis according to molecular subtype demonstrated a significant association between GATA3 expression and immunohistochemically defined molecular classification (χ²=8.393, df=3, p=0.038). GATA3 positivity was highest among hormone receptor-positive tumors, whereas triple-negative breast cancers exhibited the lowest expression.

Conclusion

GATA3 expression is significantly associated with lower histological grade, hormone receptor positivity, and hormone receptor-positive molecular subtypes in invasive ductal carcinoma of the breast. These findings support the role of GATA3 as a reliable marker of luminal differentiation and emphasize its diagnostic value in the immunohistochemical evaluation and molecular characterization of breast carcinoma.