Abstract P5-01-06: Differences in FGF1 and FGFR2 expression in BRCA1-associated, BRCA2-associated, and sporadic breast carcinomas

Abstract

Abstract Introduction. In contrast to BRCA1-associated breast cancer, a distinctive phenotype for BRCA2-associated carcinomas has not been identified yet as there is no clear distinction between BRCA2- and non-BRCA mutation related or sporadic carcinomas. Recently, studies suggest overexpression of fibroblast growth factor 1 (FGF1) and fibroblast growth factor receptor 2 (FGFR2) in BRCA2 related cancers. The aim of the study was therefore to investigate whether there is differential expression of FGF1 and/or FGFR2 between BRCA2 related and sporadic and BRCA1 related cancers. This would reveal the usefulness of FGF1 and FGFR2 immunohistochemistry in daily pathology practise. Method. Invasive breast carcinomas of 33 BRCA1 and 22 BRCA2 germline mutation carriers and a tissue microarray containing 104 sporadic invasive breast carcinomas were immunohistochemically stained for FGF1, FGFR2, estrogen receptor (ER), progesterone receptor (PR), HER2, epidermal growth factor receptor 1 (EGFR), cytokeratin (CK) 5/6 and CK14. Results. FGFR2 expression was seen in 68.2% and 79.0% of BRCA2-associated and sporadic carcinomas respectively, in contrast to 22.6% of BRCA1-associated tumors (p = 0.000). FGF1 expression was seen in 72.7% of BRCA2-associated carcinomas and in 45.2% and 41.8% in BRCA1-associated and sporadic carcinomas, respectively (p = 0.032). Conclusion. FGFR2 expression differs significantly between BRCA1- and BRCA2 associated breast carcinomas but not between BRCA2 and sporadic cancers. FGF1 expression differs significantly between BRCA2-associated and sporadic carcinomas and could be used as a BRCA2-specific biomarker. Citation Information: Cancer Res 2012;72(24 Suppl):Abstract nr P5-01-06.