Aim: To study the expression of  Ki–67  in invasive ductal and invasive lobular carcinomas

of  breast and analyze its utility in predicting the response to chemotherapy and as a

prognostic marker. Materials and methods: A total of fifty breast carcinoma specimen

were  investigated comprising of forty  invasive ductal carcinomas and ten invasive lobular

carcinomas. Haematoxylin and Eosin slides of all the tissues were evaluated.The formalin

fixed, paraffin embedded blocks were sliced in 3–4 µm thickness for IHC. The Avidin Biotin

complex (ABC) detection system was used. Immunoreactivity was regarded as positive when

brown staining was localized to the nucleus of the tumor  cells. Results:  Ki–67 expression

was observed in invasive ductal carcinoma(IDC) and invasive lobular carcinoma(ILC) and

graded as  low, intermediate and high.

Conclusion

 Out of the 40 cases of  invasive ductal carcinoma Ki67 was found to have  high expression in

20 (50%) patients, intermediate expression in 13(32.5%) patients and low in 7(17.5%)

patients. Out of the 10 cases of invasive lobular carcinoma Ki–67 was found to have high

expression in 5(50%) patients intermediate expression in 3(30%)  patients and low expression

in 2(20%) patients.