Triple Negative and Younger Cases in Breast Cancer Showed Higher Ki-67 Proliferation Index, Nuclear Grade and Histological Grade

Abstract Triple negative (TN) and younger cases in breast cancer have poorer clinical outcome data. We evaluated the relationship between outcome of triple negative and younger cases and the proliferation potency of breast cancer cells. 94 cases of operated breast cancer were classified by subtype according to 2011 St. Gallen consensus meeting. Each subtype group and younger patients (=or<45) were investigated Ki-67 proliferation index indicated proliferation potency of cancer, nuclear grade (NG) and histological grade(HG). Out of 94 cases 48 were classified as Luminal A, 30 as Luminal B, 8 as HER2 and 8 as TN. The average proliferation index of Ki-67 was 6.4 ± 3.7 in Luminal A, 24.6 ±11.2 in Luminal B, 20.2 ± 6.6 in HER2, and 62.6 ± 15.7 in TN. There was a significant higher proliferation index of Ki-67 in the TN group. There were significantly higher NG and HG in the TN group compare with Luminal A and B. Mean Ki-67 proliferation index, NG and HG in cases which were 45 years old and less was significantly higher than those in cases which were more than 46 years old. The poor prognosis in the TN group and younger patients is supposedly caused by the proliferation potency, NG and HG in breast cancer.