Introduction/Background Breast cancer represents a heterogenous disease with different biological profiles. Regardless of recent developments in disease management, breast cancer remains a disease with a lifetime recurrence risk. GATA binding protein 3 (GATA3) represents a potential biomarker of breast cancer with prognostic properties. The aim of this study was to evaluate the correlation of GATA3 expression with clinico-pathological features of more agressive breast cancer.

Methodology Women were recruited prospectively to this study between February 2019 – March 2021 at the University Medical Centre Maribor, Slovenia. Clinical data was analyzed in correspondance to GATA3 staining. Stainig scores were determined according to unit standards with multiplying the percentage of cancer cells and intensity score. A final score of low, medium or high expression of GATA3 was determined by a board certified pathologist. Continous variables were expressed as median variables (standard deviation) and proportions were reported as percentages. Immunohistochemical scoring was analyzed using a non-parametric test to compare groups. All analyses were done using SPSS for Mac.

Results Sixty-one women with breast cancer participated in this study. The median age was 64 years (min 31 – max 88). Most women had invasive ductal carcinoma (n=46, 77%), followed by invasive lobular carcinoma (n=9, 14.8%) and other histotypes (n=5, 8.3%). GATA3 immunohistochemical expression was not connected to lymph-node metastasis (p>.253), lympho-vascular invasion (p>.103), grade (p>.481), tumour size (p>.335), progesterone expression (p>.763), Ki67 expression (p>.669) or age at time of diagnosis (p>.267). GATA3 expression was only significantly connected to oestrogen receptor expression (p<.030).

Conclusion GATA3 significantly correlates with ER receptor expression, however more detailed large group analyses are needed for clinicopathological comparisons among different histological subtypes or other markers.