Comparison of ER, PR and HER2 Expression between Breast Carcinoma Fine Needle Aspiration Samples and Corresponding Surgical Pathology Specimens – A Large Retrospective Study
Poonam Vohra, Maria Serrano, Yunn Yi Chen, Britt-Marie Ljung. University of California, San Francisco, CA; San Rafael Medical Center, San Rafael, CA
Background: Determination of estrogen receptors (ER), progesterone receptors (PR) and HER2 is standard in breast carcinomas. ER, PR and HER2 are routinely evaluated on fine needle aspiration (FNA) cell blocks (CB) and tissue sections using immunohistochemistry (IHC). Whether FNA CB are reliable for these biomarkers remains controversial. The objective of this study is to determine concordance between these biomarkers on cell blocks versus tissue blocks.
Design: A large retrospective study was performed in 150 consecutive cases from 2002 to 2009. FNA CB and corresponding tissue blocks of invasive breast carcinoma were identified. We compared ER, PR and HER2 immunohistochemical expression in formalin-fixed FNA CB and subsequent formalin-fixed tissue blocks from the same patient. Tissue blocks were formalin fixed per ASCO/CAP guidelines for HER2 (IHC). Fluorescence in situ hybridization, performed on a subset, was included in the analysis.
Results: We found agreement in 98% of cases with positive ER expression and 100% agreement with negative ER expression, using findings on tissue blocks as gold standard. PR correlation was slightly lower (96%) than ER for positive expression but 100% agreement with negative expression. HER 2 testing demonstrated > 95% agreement between CB and tissue block samples.
Conclusions: This study is the largest study to date, to our knowledge, correlating ER, PR and HER2 determination on cell block and subsequent tissue samples. In addition, this study is different from most previous correlation studies in that cell block samples were fixed directly in formalin. Based on the excellent concordance found we conclude that FNA CB samples are reliable for the assessment of these biomarkers.
Monday, March 4, 2013 1:00 PM
Poster Session II # 63, Monday Afternoon