Role of Diagnostic Immunohistochemistry in correlation of ER,PR,HER- 2/neu status and Modified Scarff Bloom Richardson Histological Grading in Breast Carcinoma

Introduction: Breast carcinoma is the most common malignant tumour among women. Annually about one million women are diagnosed with breast cancer worldwide. There is an increased trend in the detection of breast carcinoma, which can be attributed to increased mammographic screening. But the mortality has decreased due to early screening which detects the tumour at an early curable stage and also by means of better effective treatment modalities. The currently used histologic grading system is known as the Elston-Ellis modification of Scarff-BloomRichardson grading system. There is a significant correlation between histologic grade and frequency of recurrence, disease free survival and overall length of survival regardless of clinical stage in invasive breast carcinoma. Aim and Objective: To correlate histological grading by modified Scarff-Bloom-Richardson grading system with biomarkers ER, PR and HER2/neu status in invasive breast carcinoma using diagnostic immunohistochemistry. To assess the proportion of different grade of invasive breast carcinoma by modified ScarffBloom-Richardson grading system. To study ER, PR and HER-2/ Neu reactivity in the patient of breast carcinoma. Material and Methods: An observational, prospective study of 45 cases was done during June 2020 to August 2021 in the Department of Pathology, Govt. Medical College, Bhavnagar. Approval was taken from Institutional Ethical Committee before commencement of the present study, the EC approval number is 961/2020. In every case the standard grossing protocol of the modified radical mastectomy specimen was followed according to CAP guidelines for invasive ductal cell carcinoma of breast. After a detailed specimen description, representative tissue bits were taken. These tissue bits were subjected for routine processing in an Automatic Tissue Processor Electra by Yorco TM and embedded in paraffin wax. Three to four micron thick sections were taken from paraffin embedded blocks using Lieca RM 2125 RT microtome and were stained using Hematoxylin and Eosin (H andamp; E) for histopathological study. Results: The predominant histologic type was Invasive Ductal Carcinoma, No Special Type (IDC, NST) consisting of 27 cases (60%) followed by 8 cases (18%) with Invasive lobular carcinoma. There were 10 cases of IDC SPECIAL TYPE. Majority of tumours belonged to Modified Bloom Richardson Grade 2 (33.3%) from IDC NST histological subtype. As per molecular classification, most of tumours found to be Luminal Type A belonged to Grade 2 (62%). Majority of IDC, NST (27 cases, 60 %) were Luminal A type. A significant correlation was found between histological subtypes and molecular classification of invasive breast carcinoma. P value (0.0037).Conclusion: The ER, PR and HER2 status correlate well with histopathological grading. The inter-relationship between ER, PR and HER2 has come to have an important role in the management of the breast cancer. Hence, immunohistochemical assessment of ER, PR and HER2 status along with histopathological grading should be incorporated as a routine investigation to guide the clinicians in making correct choice of treatment to increase the disease-free survival for the patient.