Role of Irisin/FNDC5 (rs3480) Single Nucleotide Polymorphism in Breast Cancer.

Background: Breast cancer is the most common malignancy among women and remains a leading cause of cancer-related mortality. Previous studies suggest that the FNDC5/irisin gene may exert a protective role against breast cancer, as reduced expression levels have been linked to the presence of metastasis. The present study aims to investigate the potential association between single nucleotide polymorphisms (SNPs) in the irisin gene and the risk of breast cancer. In addition, it will analyze the distribution of these genetic alleles in relation to different clinical parameters of the disease Patients & Methods: This cross-sectional study was conducted from July 2023 to May 2024 and included 50 pathologically confirmed breast cancer patients recruited from the Clinical Oncology Department, Faculty of Medicine, Sohag University. A control group of 50 healthy volunteers, with no clinical evidence of any neoplastic disorder, was also enrolled. Patient characteristics were retrieved from the local databases of the Clinical Oncology Department at Sohag University. Results: Our study revealed no significant differences between cases and controls regarding age or family history. Circulating irisin levels showed a highly significant reduction in breast cancer patients compared to controls (P < 0.001). In addition, a statistically significant association was identified between genotypic distribution and tumor pathology (P < 0.005). The GG genotype was predominantly linked to invasive lobular carcinoma (33.3%), whereas the AA and AG genotypes were more frequently associated with invasive ductal carcinoma Conclusion: The study concluded that circulating irisin appears to play a protective role against breast cancer, as its levels were markedly lower in patients compared to controls. While irisin gene polymorphism may not represent a direct risk factor for breast cancer, it could influence tumor behavior of breast cancer and disease severity.