Comparative Evaluation of Immunohistochemical Expression of Estrogen Receptor, Progesterone Receptor and HER2 in Fine Needle Aspiration Cell Blocks and Surgical Biopsies in Primary Breast Carcinoma

ABSTRACT

Introduction: Breast carcinoma is the leading cause ofcancer mortality among females. Estrogen and Progesteronereceptors (ER, PR) and HER2 have been used for theranosticsin breast cancer. Fine needle aspiration cytology (FNAC)can yield highly cellular material for cytological diagnosis.Predictive biomarker assessment can be done on cytologicspecimens to know the patient’s eligibility for endocrinetherapy and anti- HER2- targeted therapy. Cell blocks furthercan increase the diagnostic accuracy through morphology andthe use of immunohistochemistry (IHC). The present studywas undertaken to evaluate immunohistochemical expressionof estrogen receptor, progesterone receptor and HER2 in fineneedle aspiration cell blocks and surgical biopsies in primarybreast carcinoma cases.Material and methods: IHC for ER, PR and HER2 wasassessed on 50 pre chemotherapy breast carcinoma cell blocks(fixed in 10% formalin) and subsequent tissue sections.The scoring for ER/ PR was done according to ASCO/CAPguidelines. Strong circumferential membrane staining ingreater than 10% of tumor cells was considered positive forHER2.Results: Immunostaining assessment on cell block and theircorresponding tumor tissues showed a good concordance ER(92%), PR (92%) and HER2 (93.75%). Taking histology asthe final outcome, the sensitivity of ER, PR and HER2 on cellblock was 92.30%, 86.36% and 91.67%, respectively, whilespecificity was 92.85%, 96.43% and 94.44%, respectively.Conclusion: IHC on cell blocks from breast carcinoma casesis useful especially when planning neoadjuvant chemotherapy.The pre analytic and analytic variables should be validated tooptimize the diagnostic utility of cell blocks.