On protein level, MMP-1 expression was found in 39 of 41 (95%) EAC with BE, in 19 of 19 (100%) EAC without BE, in 6 of 10 (60%) ESCC, and in 10 of 18 (56%) BE without IN. The gene discussed is MMP1; the disease is esophageal squamous cell carcinoma.