Incidence and significance of GATA3 positivity in pancreatic ductal adenocarcinoma and cholangiocarcinoma

GATA3 is a transcription factor involved in the development and differentiation of lymphocytes, breast, and hair follicles. The protein is a useful immunohistochemical (IHC) marker for supporting diagnoses of breast or urothelial carcinoma. This can be especially helpful in metastatic neoplasms to help delineate site of origin. GATA3 is also reportedly positive in a percentage of pancreatic ductal adenocarcinomas (PDACs) and cholangiocarcinomas (CCs), but no study has closely evaluated this relationship with respect to clininopathologic features or patient outcome. Using tissue microarrays, we analyzed 240 PDACs and 60 CCs with GATA3 IHC and compared expression to various clinical and pathologic parameters. Overall, GATA3 positivity was seen in 16% of PDACs and 5% of CCs. GATA3 positivity in PDAC cases was more common in male patients (P=0.013). GATA3-positive PDACs trended toward worse survival on multivariate analysis (P=0.074). The only 3 GATA3-positive CCs were poorly differentiated (P=0.069); low case number precluded multivariate survival analysis for CCs. GATA3 positivity can occur in carcinomas of the pancreatobiliary system, which should be considered during IHC workup of neoplasms of unclear origin. This positivity seems to have minimal relevance to patient outcome.