Comparison of Clinicopathological Characteristics of BRCA1 and BRCA2 Carriers with Breast Cancer: The Role of Ki-67 Index
Received Date : 30 Jan 2021
Accepted Date : 23 Sep 2021
Available Online : 06 Oct 2021
Recep AKa, Cengiz KARAÇİNa, Taha BAHSİb, Ömür Berna ÖKSÜZOĞLUa
aDepartment of Medical Oncology, University of Health Sciences Dr. Abdurrahman Yurtaslan Oncology Training and Research Hospital, Ankara, TURKEY
bDepartment of Medical Genetic, University of Health Sciences Dr. Abdurrahman Yurtaslan Oncology Training and Research Hospital, Ankara, TURKEY
Doi: 10.37047/jos.2021-81821 - Article's Language: EN
J Oncol Sci. 2021;7(3):91-7
ABSTRACT
Objective: To elucidate the clinicopathological differences between breast cancer 1 (BRCA1) and BRCA2 carriers among patients
with breast carcinoma. Material and Methods: The present retrospective study explored the demographic and clinicopathological features
of 57 BRCA carriers with breast cancer. The age, family history, tumor Ki-67 index, tumor grade, hormone receptor status (estrogen and
progesterone), human epidermal growth factor receptor 2 status, tumor T and N Stage, tumor multifocality, and tumor treatment modalities
(surgical or adjuvant/neoadjuvant chemotherapy) were recorded for each patient from the hospital automation system. Results: The patients
with a median age of 39 (range: 23-68 years) years comprised 35% BRCA1 and 65% BRCA2 carriers. Higher median Ki-67 index was revealed
for the BRCA1 group than for the BRCA2 group (40% vs. 80%, p=0.006). The proportions of patients with estrogen receptor (+) and
progesterone receptor (+) tumors were 35.0% and 35.0%, respectively, in the BRCA1 group, whereas 75.7% and 73.0%, respectively, in the
BRCA2 group (p value 0.003 and 0.005, respectively). The BRCA1 group demonstrated significantly higher proportion of triple-negative patient
rate as compared to the BRCA2 group (21.6% vs. 55.0%, p=0.011). Multivariate logistic regression analysis conducted with the Ki-67
index, estrogen receptor status, progesterone receptor status, and triple-negative disease status identified the Ki-67 index as the only independent
predictive factor that could distinguish the BRCA1 from the BRCA2 mutation. A high Ki-67 index (>45%) was correlated with the
BRCA1 mutation (odds ratio: 0.970, 95% confidence interval: 0.943-0.999, p=0.044). Conclusion: A high Ki-67 index is more frequently
prevalent in BRCA1 carriers than in BRCA2 mutation carriers among patients with breast cancer.
Keywords: BRCA1 protein; BRCA2 protein; breast; breast neoplasm