EXPRESSION OF GATA 3 IN EPITHELIAL TUMORS.

Objective: To assess the expression of GATA-3 among epithelial tumors of four organs including invasive mammary carcinoma, prostatic adenocarcinoma, colorectal carcinoma and high grade serous carcinoma of ovary. Study Design: Case series study. Place and Duration of Study: The study was performed at Shaukat Khanum Memorial Cancer Hospital and Research Center, from Jul 2017 to Dec 2017. Methodology: Twenty cases of each of these tumors were collected and stained with ready to use GATA-3 immunohistochemical stain (Cell marque (L50-823) mouse monoclonal antibody) using BOND III Leica automated immunostainer. The expression of the antibody was assessed by two histopathologists. Diffuse nuclear staining in more than 30% of tumor cells was considered as positive. Results: All the breast carcinomas showed diffuse strong positivity in tumor cells, while all the cases of prostatic adenocarcinoma showed negative staining. Aberrant and focal staining was observed in a few cases of high grade serous and colorectal carcinomas. Three cases of high grade serous carcinoma showed weak nuclear staining in 10% of cells. Only one case of colorectal carcinoma showed weak nuclear blush in 10 to 20% of tumor cells. Conclusion: GATA-3 was found a sensitive and specific marker for mammary carcinomas. It is a useful diagnostic tool and should be included in a panel of immunohistochemical markers when working on a metastatic tumor of unknown origin. [ABSTRACT FROM AUTHOR]