Association of serum annexin A1 with treatment response and prognosis in patients with esophageal squamous cell carcinoma

Objective: Annexin A1 (ANXA1), a calcium-dependent phospholipid binding protein, is known to be regulated by microRNA-196a (miR-196a) in esophageal adenocarcinoma, and its high expression in tumor tissue is correlated with the poor prognosis of esophageal squamous cell carcinoma (ESCC). However, the role of ANXA1 in the serum of patients with ESCC remains unclear. Materials and Methods: In this study, we used enzyme-linked immunosorbent assay to evaluate the levels of ANXA1 and real-time polymerase chain reaction to detect the expression of miR-196a in the serum of ESCC patients (healthy donors as controls) and evaluated the relationship between ANXA1 and clinical outcomes. Results: The results showed that the level of serum ANXA1 in ESCC patients was significantly lower than that in controls (P = 0.001) but increased after chemoradiotherapy (P = 0.001). There was no correlation between the baseline level of serum ANXA1 and the short-term efficacy of treatment (P = 0.26) as well as the 1-year progression-free survival (PFS) (P = 0.094). However, there existed a significant correlation between the increases of serum ANXA1 expression and the 1-year PFS (P = 0.04). A higher increase (>2-fold of baseline) in the serum ANXA1 levels was correlated with a poorer PFS (hazard ratio = 3.096, 95% confidence interval 1.239-7.861). There was an inverse correlation between the expressions of miR-196a and ANXA1 in serum (Pearson's correlation of -0.54, P = 0.021). Conclusion: Our data revealed that the expression of serum ANXA1 in ESCC patients increases after chemoradiotherapy and the increased fold change in serum ANXA1 confers independent negative prognostic impact in ESCC. The higher the increase in serum ANXA1 levels, the poorer the outcome.