Serum interleukin-8 as a potential diagnostic biomarker in esophageal squamous cell carcinoma.

BACKGROUND: Esophageal squamous cell carcinoma (ESCC) has poor prognosis mainly due to the difficulty of making early diagnosis. Therefore, novel biomarkers are critically needed. OBJECTIVE: We aimed to investigate the diagnostic value of serum interleukin-8 (IL-8) in ESCC. METHODS: Data mining of TCGA was used to analyze expression level of IL-8 mRNA in esophageal carcinoma. Serum levels of IL-8 were measured in 103 ESCC patients and 86 normal controls by ELISA. Receiver operating characteristic (ROC) curve was used to evaluate its diagnostic accuracy. RESULTS: IL-8 mRNA expression level and serum IL-8 concentration were both statistically higher in patients than normal controls (P < 0.001). ROC curve demonstrated that the optimum diagnostic cut-off for serum IL-8 was 80.082 pg/mL, providing an area under the curve (AUC) of 0.694 (95% CI: 0.620-0.768), with specificity of 86.0% and sensitivity of 42.7%. The AUC for early-stage ESCC was 0.618 (95% CI: 0.499-0.737), with sensitivity of 35.3% and specificity of 86.0%. Kaplan-Meier analysis and the log-rank test indicated that IL-8 may not be a prognostic predictor for ESCC. CONCLUSIONS: Serum IL-8 was highly expressed in ESCC patients and may be a potential marker for early diagnosis of ESCC.