It showed that: i) ENO1 production is abnormally elevated in cancer cells in both ESCC and EAC, increasing during tumor stage progression and in non-dysplastic BE, the premalignant condition that predisposes to the development of EAC, ii), unexpectedly, EAC patients exhibited significantly lower ENO1 plasma levels compared to normal subjects, and iii) both in situ and systemic ENO1 levels showed no significant correlation with overall survival of the patients. Here, ENO1 is linked to esophageal squamous cell carcinoma.