Establishment of Correlation of Ki-67 Proliferative Index Expression in the Peritumoral Tissue with Tumor Mass in ER (Estrogen Receptor) Positive Breast Carcinoma

Background: Breast carcinoma is the second most frequently occurring malignant tumor. It usually arises in a multistep fashion from intermediary lesions to invasive cancer. Identifying such predominantly occurring lesions adjacent to malignancy and studying of Proliferative Ki-67 index and (ER) status in such lesions and substantiate their possible identity as a premalignant lesion. The study tries to establish the lesions which have the potential for progression to overt malignancy, thereby indicating early identification and appropriate treatment.

Aim: To establish a correlation in the expression of Ki-67 proliferative index in the peritumoral tissue with tumor mass of ER-positive breast carcinomas.

Objectives: 1.To study the expression of ER in breast tumor mass. 2. To study expression of Ki-67 proliferative index in breast tumor mass and peritumoral tissue. 3. To assess the expression of Ki-67 proliferative index in breast tumor mass and peritumoral tissue. Study design: Observational prospective study.

Materials and Methods: 32 mastectomy specimens of diagnosed cases of breast carcinoma sent to the Histopathology Section are studied. Gross features are described and the histopathological section stained by (H & E) stain and immunohistochemistry using monoclonal antibody to (ER) and proliferation-associated antigen (Ki-67) are studied. Statistics: Chi-square test, Spearman’s rank-order correlation coefficient, and software used in the analysis were SPSS 22.0 version and Graph Pad Prism 6.0 version and p<0.05 is considered as the level of significance.

Results: In this study out of 32 ER-positive cases, 24 showed positivity for Ki-67 in tumor mass and 22 cases showed high Ki-67 in peritumoral tissue. Maximum lesions were proliferative lesions with atypia like ADH and DCIS.

Conclusion: Ki-67 is an accurate nuclear proliferative marker to assess cell proliferation status. In breast carcinoma adjacent peritumoral lesions show a high proliferative index which suggests a link and a trail of generation of premalignant lesions converting to invasive carcinoma. Proliferative lesions with and without atypia, moderate epithelioid, atypical ductal hyperplasia, and DCIS more or else equals IDC for Ki-67 proliferative index. Such cases should be regularly followed up for progression of these lesions to malignancy.