Comparison between clinical significance of serum CXCL-8 and classical tumor markers in oesophageal cancer (OC) patients.

C-X-C motif chemokine 8 (CXCL-8), known as interleukin-8, is a pro-inflammatory cytokine which acts as a chemotactic factor, mainly for leukocytes. CXCL-8 is produced by malignant cells, and therefore it can stimulate the growth and progression of various neoplasms, including oesophageal cancer (OC). The aim of the current study was to measure serum concentrations of chemokine CXCL-8 in OC patients and establish whether this protein might be considered a potential candidate for a tumor marker in the diagnosis and progression of OC. The study included 50 OC subjects (32 patients with squamous cell carcinoma of oesophagus-OSCC, 18 patients with adenocarcinoma-OAC) and 26 healthy volunteers. Serum CXCL-8 concentrations were measured using immunoenzymatic assay (ELISA). CRP levels were determined by immunoturbidimetric method, while classical tumor marker levels were measured using chemiluminescent immunoassay. CXCL-8 concentrations were significantly higher in OC patients compared to healthy controls. We demonstrated significant differences between CXCL-8 concentrations and depth of tumor invasion (T factor) in OC patients and OSCC subgroup. In addition, CXCL-8 levels were found to correlate positively with T factor and CRP concentrations. The diagnostic sensitivity, negative predictive value and the area under ROC curve (AUC) of CXCL-8 were higher than those of classical tumor markers. Our findings suggest the potential usefulness of CXCL-8 in the diagnosis and progression of OC. However, due to the non-specific nature of this chemokine, further research is needed to clarify the usefulness of CXCL-8 as a tumor marker of OC.