In the subgroup analyses of AUROC, the adding of plasma MMP1 (dichotomized by 9.67 ng/mL) to different uses of substances (smoke, alcohol or areca quid) made possible significantly better detection rate of ESCC in those who consumed any one or two substances (Fig. 2B, AUROC = 0.793 vs. 0.757, difference = 0.0361, p = 0.0013 and Fig. 2C, AUROC = 0.876 vs. 0.858, difference = 0.0175, p = 0.0097). The gene discussed is MMP1; the disease is esophageal squamous cell carcinoma.