Compared with those with plasma MMP1 ≤ 9.67 ng/mL, subjects with higher levels had 9.0 times the risk of ESCC after adjustment for other covariates (AOR = 9.0, 95% CI = 2.2–36.0, p = 0.0019) (Table 2). Here, MMP1 is linked to esophageal squamous cell carcinoma.