2Department of Pathology, Istanbul University-Cerrahpasa Faculty of Medicine, Istanbul-Turkey
3Department of Public Health, Merzifon District Health Directorate, Amasya-Turkey DOI : 10.5505/tjo.2021.2851 OBJECTIVE
Immunohistochemical Ki-67 index is a useful method to determine the prognosis. We aimed to evaluate the association of Ki-67 score, using 14% and 20% cut-off values, with clinicopathological parameters in invasive breast carcinomas.
METHODS
Pathology reports of 162 females were retrospectively reviewed and parameters including age, menopausal
status, multifocality/multicentricity (MF/MC), tumor size, histological type, grade, lymphovascular
invasion (LVI), perineural invasion, axillary lymph node status, ER, PR, HER2 status, Ki-67 index,
and molecular subtype were recorded. The cases were grouped according to two separate Ki-67 cut-off
values (high: ?14% and ?20%, low <14%, and <20%). Ki-67 score was compared with other clinicopathological
parameters statistically using Chi-square test.
RESULTS
When the Ki-67 score was grouped according to 14% or 20% cut-off values, it was found to be associated
with similar clinicopathological parameters. There was a significant correlation between high Ki-67
score and high grade (p<0.001, p<0.001), LVI (p=0.002, p=0.022), ER negativity (p=0.001, p<0.001).
When ER expression was grouped as negative, low positive and positive, similar results were obtained
(p=0.003, p=0.001). There was a significant association between Ki-67 score and molecular subtypes
(p<0.001, p<0.001): Ki-67 score was higher in cases that belong to Luminal B subtype and lower in cases
that belong to Luminal A in comparison to others. Ki-67 score had no association with age, menopausal
status, MF/MC, tumor size, perineural invasion, axillary lymph node involvement, PR, and HER2 status.
CONCLUSION
Standardization of interpretation of Ki-67 proliferative index and cut-off value for scoring will improve
the demonstration of the prognostic signification of Ki-67 in invasive breast carcinomas.