Research Article

Immunohistochemical study of ki67 biomarker to identify the intrinsic molecular types of breast cancer in women residing in Al-Najaf Al –Ashraf governorate

Abstract

The current study comprised sixty Iraqi female patients with breast cancer, ranging in age from 35 to 75 years old, who were diagnosed between January 19, 2023 and May 10, 2025. The current study used paraffin-embedded of female breast carcinoma sections that confirmed histological diagnosis such as tumor size, differentiation degree, and forms of invasive breast cancers. Immunohistochemical biomarker expression of ki67 cases were categorized into two groups based on proliferation index: high (≥25%) and low (<25%) expression levels, with invasive breast cancer and correlation with different clinicopathological variables, in the age group under 40 years, Ki-67 expression was high (>25%) in 3.3% and low (<25%) in 11.7%. Among patients aged 40–49 years, 67 high expression was seen in 8.3%, and low expression in 21.7%. In the 50–59-years age group Ki-67 was expressed at high levels in 10% and low levels in 20% of the cases. Older patients (>60 years) High Ki-67 expression was found in 6.6%, and low expression in 18.3%. Women in the 50–59 age group demonstrated the highest levels of Ki-67, suggesting increased tumor cell proliferation. Elevated Ki-67 expression in older age groups aligns with the observed tendency for higher tumor grades and more aggressive tumor behavior in late-onset breast cancer. Statistical analysis using alphabetical lettering (A, B, C, D) indicated significant differences between age groups at P ≤ 0.05. In luminal A subtype, high Ki-67 expression (>25%) occurred in 10%, while low expression (<25%) was seen in 46.6%, showing significant difference (P ≤ 0.05). Luminal B tumors showed high expression in 6.6% and low in 5%, also statistically significant. HER2-enriched tumors exhibited high Ki-67 in 3.3% and low in 16.3%, with significant variation (P ≤ 0.05). Triple-negative tumors showed high expression in 3.3% and low in 8.3%, with notable difference. No grade I tumors showed Ki-67 expression. In grade II, high expression was 13.8%, low 63.3%, with significant differences. Grade III had high expression in 10% and low in 13.8%, also showing statistical significance. These findings suggest Ki-67 is a valuable marker for assessing proliferation across subtypes and grades, especially in luminal A and grade II tumors.

Author's Information:

Alaa Talib Dawood (ORCID), Department of Human Anatomy, College of medical & Pharmaceutical Science, Faculty of medicine, Jabir Ibn Hayyan University, Iraq
Ali Hassan Abood (ORCID), Department of Biology, Faculty of Science, Kufa University, Iraq.

How To Cite: A.T. Dawood, A.H. Abood. Immunohistochemical study of ki67 biomarker to identify the intrinsic molecular types of breast cancer in women residing in Al-Najaf Al –Ashraf governorate. Healthcare Issues, 4(2): 1–9, 2025. https://doi.org/10.58614/hi421