Plasma anti-FDX1 autoantibody as a potential biomarker for detection and diagnosis of breast cancer.

Autoantibodies have emerged as highly valuable biomarkers for cancer detection. Ferredoxin 1 (FDX1), a key cuproptosis regulator, significantly influences breast cancer prognosis. This study aimed to investigate whether the anti-FDX1 autoantibody can serve as a novel biomarker for breast cancer detection and diagnosis. Anti-FDX1 levels were detected in plasma from 336 breast cancer patients (BC), 220 patients with benign breast nodule (BBN), and 236 normal controls (NC) using ELISA assay. Anti-FDX1 levels in BC were lower than that in NC and BBN. Subgroup analysis revealed enhanced diagnostic efficacy in Luminal A patients aged <50 years: compared with NC, AUC = 0.746 (95% CI: 0.666-0.825); compared with BBN, AUC = 0.695 (95% CI: 0.611-0.780). The combined model of anti-FDX1 and CEA further improved the diagnostic efficacy. The anti-FDX1 autoantibody had high diagnostic value for breast cancer, and the combined model with CEA further optimized the early screening and diagnosis for breast cancer in young women.