GATA3 aids in distinguishing fumarate hydratase-deficient renal cell carcinoma from papillary renal cell carcinoma.

GATA3 has been reported to be positive in clear cell papillary renal cell carcinoma and papillary renal neoplasm with reverse polarity. However, its features in high-grade RCC remain unclear. Despite the emergence of novel renal entities, FH-deficient RCC remains one of the most aggressive renal neoplasms. The diagnosis is mainly based on the loss of FH at the protein level. Previous studies have shown that inclusion-like nuclei, multiple architectural patterns, FH loss, and 2SC positivity can differentiate FH-deficient RCC from other RCC. In some FH-deficient RCC cases, FH is normally expressed and is difficult to diagnose. This study included 11 FH-deficient RCC, and GATA3 showed different expression in seven cases. However, 147 papillary renal cell carcinomas were included, and GATA3 expression was negative. A comparison of clinicopathological aspects between 11 FH-deficient RCC and 30 high-grade PRCC showed statistical significance in age, size, multiple architectural patterns, inclusion-like nuclei, and prognosis. However, PRCC exhibited similar characteristics. CK7, GATA3, and FH profiles were also statistically significant. Different chromosomal alterations were found in FH-deficient RCC, and chromosomal alterations were not different between FH-deficient RCC and PRCC. GATA3 was positive in 33 % (7/21) of collecting duct carcinomas and negative in other high-grade renal neoplasms. GATA3 is negative in PRCC, but can be positive in FH-deficient RCC and collecting duct carcinoma. GATA3 expression may indicate a worse outcome in high-grade RCC with papillary architecture. We recommend GATA3 IHC for the differential diagnosis and prognostic assessment of high-grade RCC with papillary architecture.