Correlation of mitotic activity and Ki 67 with BR score and molecular classification in carcinoma breast

Abstract

Background: To determine if mitotic activity played a role in classifying breast cancer in terms of its biological behaviour. We investigated the prospect of identifying a more meaningful cell proliferation marker for categorising treatment-naive breast cancer. Methods: The 150 cases diagnosed as invasive breast carcinoma in the histopathology section were systematically studied for the clinical, gross, and microscopic features. Results: the 50% patients were grade 2 (75), 41% were grade 3 (71) and 9% (14) were grade 1 in present study. The distribution of intrinsic subtypes was luminal A 25% (38), luminal B 59% (88), HER2 enriched 10% (15), basal 6% (9). Out of 150 cases, 29% (43) cases were T1, T2 were 65% (97), T3 were 2% (4), T4 were 4% (6). Mean Ki 67 was 15.6±8.8 in grade 1, 23.3±15.4 and 38.2± in grade 3. There was significant difference between I and III, and II and III (p<0.05). Mean mitotic count in grade 1 was 5.4±2.7, in grade 2 it was 9.7±13.5, in grade 3 it was 16.1±6.9. There was significant difference between grade 1 and 2, grade 2 and 3, grade 1 and 3 (p<0.05). There was significant difference between T stages (p<0.05). Conclusions: Ki 67 showed a more significant statistical correlation with prognostic factors as compared to mitotic count; we feel Ki 67 is more superior to mitotic count as a prognostic factor.