EGFR Status by Immunohistochemistry in Triple-Negative Breast Cancer: An Evaluation of Prevalence and Association with Clinical and Pathological Parameters.

Background & Objective: This study aimed to evaluate the expression patterns of epidermal growth factor receptor (EGFR) in patients with triple-negative breast cancer (TNBC) in Kerman, Iran, and investigate its association with various clinicopathological factors. Methods: A retrospective cross-sectional study was conducted on 54 TNBC patients diagnosed between 2013 and 2022. Immunohistochemistry (IHC) was performed to assess EGFR expression levels in tumor tissue samples. Patients were classified as EGFR-positive or EGFR-negative based on IHC staining results. Clinicopathological data, including age, tumor grade, vascular invasion, lymph node involvement, Ki-67 proliferation index, presence of necrosis, ductal carcinoma in situ (DCIS), and microcalcifications, were collected. Statistical analyses were performed to examine the association between EGFR expression and clinicopathological variables. Results: EGFR expression was positive in 61.1% of the patients. A significant association was found between EGFR positivity and higher tumor histologic grade (P = 0.045), with 69.7% of EGFR-positive patients exhibiting grade III tumors compared to 38.1% in the EGFR-negative group. Although not statistically significant, EGFR-positive patients tended to be younger (median age 44 years) than EGFR-negative patients (median age 52 years) (P = 0.157). The Ki-67 proliferation index was higher in EGFR-positive patients (median 60.0%) compared to EGFR-negative patients (median 47.5%). Conclusion: EGFR expression is significantly associated with higher tumor grade, suggesting a correlation with more aggressive tumor behavior. EGFR may serve as a potential prognostic marker and therapeutic target in TNBC. Further research with larger cohorts is recommended to validate these findings and explore the implications of EGFR-targeted therapies in TNBC management.