Association Between Neutrophil-To-Lymphocyte Ratio and Immunohistochemical Subtypes (ER, PR, HER2/Neu) In Patients with Breast Cancer

Background: Breast cancer is the most common malignancy among women worldwide. Molecular subtyping using immunohistochemical (IHC) markers estrogen receptor (ER), progesterone receptor (PR), and HER2/neu is essential for prognosis and therapeutic planning. The neutrophil-to-lymphocyte ratio (NLR), a systemic inflammatory marker, is emerging as a potential prognostic indicator. Aim: To evaluate the association between NLR and IHC subtypes of invasive breast carcinoma and explore its prognostic relevance. Methods: A retrospective analysis was conducted on 50 newly diagnosed, untreated invasive breast carcinoma patients at Saveetha Medical College between February 2024 and March 2025. NLR was calculated from complete blood counts. IHC subtypes were determined based on ER, PR, and HER2/neu expression. Patients with infections, autoimmune diseases, or on immunosuppressive therapy were excluded. Results: Mean NLR differed significantly among IHC subtypes (p = 0.02). The highest NLR values were observed in HER2-enriched and triple-negative breast cancer (TNBC) subtypes, whereas Luminal A demonstrated the lowest values. Conclusion: Elevated NLR is associated with more aggressive IHC subtypes and may serve as a cost-effective prognostic tool, particularly in resource-limited settings.