This AUC was notably higher than commonly used BC biomarkers such as CEA (AUC = 0.56, sensitivity = 0.43, specificity = 0.51) and CA 15‐3 (AUC = 0.62, sensitivity = 0.50, specificity = 0.57), indicating hsa_circ_000178's strong potential as a non‐invasive diagnostic tool for BC [65]. The gene discussed is CEACAM5; the disease is breast cancer.