Despite CEA (AUC = 0.538) and CA15.3 (AUC = 0.686), ROC curve analysis revealed that both PTEN (AUC = 0.992) and SMAD4 (AUC = 0.853) had extremely discriminative power for good differentiating BC from all non-cancer individuals (benign and healthy combined). Here, SMAD4 is linked to cancer.