GATA3 as a putative marker of breast cancer metastasis-A retrospective immunohistochemical study.

Diagnostic verification of breast cancer metastasis with histopathology and imaging analysis is essential to determine tumor staging. The aim of this study was to validate the utility of GATA3 immunohistochemistry as a diagnostic marker for breast cancer metastases and metastases of unknown primary origin. Retrospective immunohistochemical analysis of GATA3 expression in 164 breast cancer metastases diagnosed between 2004 and 2014 showed a striking difference between mammaglobin and GATA3 expression (51.2% vs 94% positivity). These findings highlight GATA3 as a more reliable and sensitive diagnostic marker for breast cancer metastases and possibly metastatic tumors of unknown origin than mammaglobin.