1. Clinical and Analytical Validation of Two Methods for Ki-67 Scoring in Formalin Fixed and Paraffin Embedded Tissue Sections of Early Breast Cancer.
- Author
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Đokić, Snežana, Gazić, Barbara, Grčar Kuzmanov, Biljana, Blazina, Jerca, Miceska, Simona, Čugura, Tanja, Grašič Kuhar, Cvetka, and Jeruc, Jera
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PROTEIN analysis , *RESEARCH funding , *BREAST tumors , *CELL proliferation , *TUMOR markers , *DESCRIPTIVE statistics , *RETROSPECTIVE studies , *MULTIVARIATE analysis , *KAPLAN-Meier estimator , *IMMUNOHISTOCHEMISTRY , *HISTOLOGICAL techniques , *DATA analysis software , *CONFIDENCE intervals , *MICROSCOPY , *SURVIVAL analysis (Biometry) , *PROPORTIONAL hazards models - Abstract
Simple Summary: Ki-67, a protein found in actively growing and dividing cancer cells, serves as an important tumor biomarker in breast cancer. A higher Ki-67 level indicates faster cell multiplication. In this study, pathologists evaluated Ki-67 using two methods: a visual whole-slide assessment and a quantitative tumor margin analysis. The study was performed in early-stage breast cancer patients. The findings revealed that Ki-67 is a reliable method for guiding clinical decision-making. Notably, a cut-off value of 20% appeared most appropriate for prognosis estimation and prediction of therapy benefit in our cohort of patients. Proliferation determined by Ki-67 immunohistochemistry has been proposed as a useful prognostic and predictive marker in breast cancer. However, the clinical validity of Ki-67 is questionable. In this study, Ki-67 was retrospectively evaluated by three pathologists using two methods: a visual assessment of the entire slide and a quantitative assessment of the tumour margin in 411 early-stage breast cancer patients with a median follow-up of 26.8 years. We found excellent agreement between the three pathologists for both methods. The risk of recurrence for Ki-67 was time-dependent, as the high proliferation group (Ki-67 ≥ 30%) had a higher risk of recurrence initially, but after 4.5 years the risk was higher in the low proliferation group. In estrogen receptor (ER)-positive patients, the intermediate Ki-67 group initially followed the high Ki-67 group, but eventually followed the low Ki-67 group. ER-positive pN0-1 patients with intermediate Ki-67 treated with endocrine therapy alone had a similar outcome to patients treated with chemotherapy. A cut-off value of 20% appeared to be most appropriate for distinguishing between the high and low Ki-67 groups. To summarize, a simple visual whole slide Ki-67 assessment turned out to be a reliable method for clinical decision-making in early breast cancer patients. We confirmed Ki-67 as an important prognostic and predictive biomarker. [ABSTRACT FROM AUTHOR]
- Published
- 2024
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