Studying on correlation between Ki-67 index and histopathological and immunohistochemical characteristics in invasive breast carcinoma

Abstract

Background: Breast cancer is the most common cancer and the leading cause of cancer death in women. Molecular subtyping of breast cancer is based on the expression of biomarkers such as ER, PR, HER2/neu and Ki-67. Among them, Ki-67 is a biomarker expressing the proliferation level of breast cancer cells, directly related to disease progression, treatment response and prognosis. Our study aims to evaluate the Ki-67 index and its relationship with histopathological and immunohistochemical characteristics in invasive breast carcinoma. Methods: A cross-sectional descriptive study in 101 paraffin-embedded specimens of patients with invasive breast carcinoma who underwent surgery at Hue University of Medicine and Pharmacy Hospital from October 2019 to June 2021. Results: Tumors with Ki-67 index ≥ 14% account for 65.3%. Breast cancer tumors with tumor size ≤ 2 cm occupy for 50.5%. Histological grade II accounts for 53.1%. The most common disease stage is stage II (40.6%). The rate of axillary lymph node metastasis is 48.5%; The ER(+) and PR(+) rates are 64.4% and 47.5%, respectively. Tumors with HER2(+) account for 32.7%. The Luminal B accounts for the highest proportion (39.4%). The Ki-67 index has a statistically significant relationship with disease stage, histological grade, axillary lymph node metastasis, ER, PR, HER2 and molecular subtypes. There is no relationship between Ki 67 and age, tumor size and histopathological type. Conclusion: Tumors with Ki-67 ≥ 14% account for a high proportion (65.3%). The Ki-67 index has a statistically significant relationship with histopathological and immunohistochemical features: stage of disease, histological grade, axillary lymph node metastasis, ER/PR hormone receptors, and other factors. HER2-positive endodermal growth and molecular subtypes. There is no significant relationship between Ki-67 and age, tumor size and histopathological type. Key words: breast carcinoma; Ki-67; histopathology; immunohistochemistry.