Utility of manually constructed large core micro-array for routine immunohistochemical assessment of ER, PR and HER2 in carcinoma breast

Aim: To compare Immunohistochemistry (IHC) results of large core Tissue micro array (TMA) with the conventional whole section for estrogen receptor (ER), progesterone receptor (PR) and HER2 expression in breast carcinoma cases. Methods: We analyzed 51 breast carcinoma cases. Large core TMAs were manually constructed with easily available materials. Immunohistochemical evaluation of ER, PR and HER2 were carried out in parallel by TMA and whole section methods for all cases as per Allred scoring system. Observed IHC scores were compared. Results: We detected a high concordance rate of 98%, 100% and 98% for ER, PR and HER2 respectively between TMA and whole sections. In addition, the use of TMA caused a significant reduction in the use of laboratory resources- reagents, slides and blocks. Conclusion: Our analysis showed various advantages of TMA over whole sections in IHC assessment. Hence, TMA can be implemented as a valuable tool in the routine assessment of breast biomarkers without compromising quality. Keywords: Tissue microarray analysis (TMA), Immunohistochemistry (IHC), Biomarkers, Breast, Carcinoma