Immunohistochemical GATA3 expression in prostate adenocarcinoma: pitfalls.

Background: Recent studies have reported aberrant GATA3 immunohistochemical expression in high-grade prostate carcinoma, raising concerns about its specificity. This study aimed to evaluate GATA3 immunohistochemical expression in prostate adenocarcinoma.

Methods: We retrospectively collected cases of primary prostate adenocarcinoma diagnosed in our pathology department(2019-2024). Clinical and pathological data, including Gleason and ISUP grades, were collected.An automated immunohistochemical analysis was performed using the anti-GATA3 antibody(Leica, L50-823). Only nuclear staining was considered positive.

Results: Fifty-eight cases have been included in the study with a mean age of 67.8 years-old. GATA3 nuclear expression was observed in 6.9% (4/58) of cases, all classified as Gleason 7 (4   +   3) and ISUP grade 3. Only the Gleason 4 or 5 components showed staining, while Gleason 3 components were negative. Additionally, benign prostate glands and seminal vesicles showed rare GATA3 expression (4/58 and 1/58 cases, respectively).

Conclusion: While GATA3 is commonly used as a marker for urothelial carcinoma, our findings indicate that it can also be expressed in prostate adenocarcinoma, particularly in higher Gleason grade components, which may pose a diagnostic pitfall. Further studies are needed to determine the clinical significance of GATA3 expression in prostate adenocarcinoma and its potential impact on tumor behavior and prognosis.