Introduction. Since colorectal cancer (CRC) is the second most commonly diagnosed malignancy in Europe and third worldwide, novel biomarkers for diagnosing the disease are critically needed. Objectives. According to our knowledge, the present study is the first to evaluate the clinical usefulness of serum CXCL-8 (C-X-C motif chemokine 8) in the diagnosis and progression of CRC compared to classical tumor marker CEA (carcinoembryonic antigen) and marker of inflammation CRP (C-reactive protein). Patients and Methods. The study included 59 CRC patients and 46 healthy volunteers. Serum levels of selected proteins were measured using ELISA (enzyme-linked immunosorbent assay), CMIA (chemiluminescent microparticle immunoassay), and immunoturbidimetric methods. Results. Serum concentrations of CXCL-8, similarly to those of the classical tumor marker CEA and inflammatory state marker CRP, were significantly higher in CRC patients than in healthy controls. There were statistically significant differences in CXCL-8 concentrations between tumor stages, as established by the Kruskal-Wallis test and confirmed by the post hoc Dwass-Steele-Critchlow-Fligner test. CXCL-8 levels were also significantly elevated in CRC patients with distant metastases compared to patients in the subgroup without metastases. Diagnostic sensitivity, predictive values for negative results (NPV), and AUC (area under the Receiver Operating Characteristic Curve-ROC curve) of CXCL-8 were higher than those of CEA, while diagnostic specificity and predictive values for positive results (PPV) of CXCL-8 were higher than those of CRP. Conclusions. Our findings indicate greater utility of CXCL-8 in comparison to the classical tumor marker CEA in the diagnosis of CRC. Moreover, serum CXCL-8 might be a potential biomarker of colorectal cancer progression.
Keywords: cancer progression; prognostic biomarkers; tumor markers.