CARM1 and breast cancer: Several circRNAs identified in our analysis, including hsa_circRNA_104310 (ZDHHC4, AUC = 0.80), hsa_circRNA_404935 (ZBTB16, AUC = 0.882), hsa_circRNA_003641 (ATM, AUC = 0.876), and hsa_circRNA_102445 (CARM1, AUC = 0.812), demonstrated strong discriminatory power across breast cancer subtypes (Figure 4A,B and Supplementary Table S3).