Expression of EMSY,a Novel BRCA2-link Protein,is Associated with Lymph Node Metastasis and Increased Tumor Size in Breast Carcinomas

Background: The EMSY gene encodes a BRCA2-binding partner protein that represses the DNA repairfunction of BRCA2 in non-hereditary breast cancer. Although amplification of EMSY gene has been proposed tohave prognostic value in breast cancer, no data have been available concerning EMSY tissue expression patternsand its associations with clinicopathological features. Materials and Methods: In the current study, we examinedthe expression and localization pattern of EMSY protein by immunohistochemistry and assessed its prognosticvalue in a well-characterized series of 116 unselected breast carcinomas with a mean follow up of 47 monthsusing tissue microarray technique. Results: Immunohistochemical expression of EMSY protein was detected in76% of primary breast tumors, localized in nuclear (18%), cytoplasmic (35%) or both cytoplasmic and nuclearsites (23%). Univariate analysis revealed a significant positive association between EMSY expression and lymphnode metastasis (p value=0.045) and larger tumor size (p value=0.027), as well as a non-significant relation withincreased risk of recurrence (p value=0.088), whereas no association with patients’ survival (log rank test, pvalue=0.482), tumor grade or type was observed. Conclusions: Herein, we demonstrated for the first time theimmunostaining pattern of EMSY protein in breast tumors. Our data imply that EMSY protein may have impacton clinicipathological parameters and could be considered as a potential target for breast cancer treatment.