The Correlation of Nottingham Prognostic Index with Immunoexpression of ER, PR, HER2, and Ki67 in Breast Cancer Tissue

Abstract

Abstract Background In the underdeveloped and developing countries, the application of immunohistochemistry (IHC) to assess the status of oestrogen receptor (ER), progesterone receptor (PR), HER2 receptor, and Ki67 proteins in formalin-fixed, paraffin-embedded tissue sections of primary invasive breast carcinoma is utterly hindered by high cost, long procedure, and need for both skilled operator and pathologist. The objective of this study was to evaluate the correlation of Nottingham prognostic index (NPI) with immunoexpression of ER, PR, HER2, and Ki67 proteins in the formalin-fixed, paraffin-embedded tissue sections of primary invasive breast carcinoma. The ethical approval reference number is IRBRTA 306/2560. Methods Two hundred and forty primary invasive breast carcinoma cases were determined their NPI which was calculated as [0.2 × maximum tumour diameter in cm] + tumour grade + axillary lymph node score. Tumour grade was given a score 1 to 3 based on the Nottingham Combined Histologic Grade system (Elston-Ellis modification of Scarff-Bloom-Richardson grading system) of primary invasive breast carcinoma. Axillary lymph node metastasis (ALNM) was given a score 1 if no ALNM, a score 2 if 1 to 3 metastatic nodes, and a score 3 if at least 4 nodal involvement. The correlation between NPI and the IHC status of ER, PR, HER2, and Ki67 was analysed at the 95% confidence interval. Results The NPI had a significant association with the immunoexpression of ER, PR, and Ki67 proteins. There was no correlation with HER2 immunohistochemical reactivity. The proposed NPI score less than 4.5 will significantly correlate with positive immunoexpression of ER and PR. The NPI score greater than or equal to 4.5 will correlate with high Ki67. Conclusion The NPI might have a role in predicting the results of ER, PR and Ki67 expression in the formalin-fixed, paraffin-embedded tissue sections of primary invasive breast carcinoma, if immunohistochemical method is unavailable.