Expression of Biomarkers Estrogen Receptor, Progesterone Receptor, HER2 in Primary Breast Tumour and Synchronous Metastatic Axillary Lymph Node

Abstract

Introduction: Estrogen Receptor (ER), Progesterone Receptor (PR), Human Epidermal growth factor Receptor 2 (HER2) status are routinely used to guide treatment decision for breast cancer. Treatment protocol in breast cancer is currently based on biomarker characteristic of primary tumour. But this biomarker status may change as the tumour progresses from primary to synchronous metastatic lymph node. Hence, it is important to know the biomarker status of these synchronous metastatic lymph nodes as it may serve as an important tool to guide management, evaluate prognosis and to anticipate the possibility of recurrent risk of primary invasive breast cancer. Aim: To study the expression of ER, PR, HER2 status in primary breast carcinoma and synchronous metastatic lymph node and to evaluate concordance and discordance between them. Materials and Methods: This study was observational, retrospective and prospective study conducted over a period of one and half years from February 2015 to October 2016 at ESI-PGIMSR, Maniktala, Kolkata, India, where 50 cases of breast carcinoma with positive axillary lymph node metastasis were studied. Haematoxylin and Eosin (H&E) sections were reviewed and representative paraffin blocks were selected. Immunostains were performed and scoring was done following standard protocols. Standard statistical methods were applied for analysis of data using chi-square test and kappa statistics and data was analysed using Statistical Package for the Social Sciences (SPSS) version 6.1.3 software. Results: Out of 50 cases the mean age of the patients was 50.56±10.5 years. Amongst ER and PR status, 24 out of 50 (48%) and 18 out of 50 (36%) were ER and PR positive respectively. HER2 positive cases were 48% i.e., 24 out of 50 cases. The overall discordance rates of ER, PR and HER2 was found to be 10%, 8%, 18%, respectively. The discordance rates of ER positive and ER negative cases were 4.2% and 15.4%, respectively. The discordance rates of PR positive and PR negative cases were 5.6% and 9.4% respectively, whereas 29.2% of HER2 positive cases were discordant in lymph node metastases. Conclusion: There was discordance between ER, PR, HER2 status of primary tumour and metastatic lymph node. Hence, assessment of these biomarker status in axillary lymph node metastases may be considered along with primary tumour in breast carcinoma work-up.