Ueland et al. [20] conducted a clinical study involving 100 subjects, including 40 patients with stable angina pectoris, 40 patients with unstable angina pectoris, and 20 healthy subjects, and found that compared to healthy subjects, patients with angina pectoris had significantly increased serum DKK1 levels; meanwhile, compared to stable angina pectoris and healthy subjects, patients with unstable angina pectoris maintained higher serum DKK1 levels [13]. Here, DKK1 is linked to intermediate coronary syndrome.