Cytoskeleton-associated protein 4 is a novel serodiagnostic marker for esophageal squamous-cell carcinoma

BACKGROUND: Recent years have witnessed significant progress in the treatment of esophageal squamous-cell carcinoma (ESCC); however, the prognosis of ESCC is still unsatisfactory. Bio-markers are required to improve identification of high-risk populations and help management of ESCC. This study was to evaluate the role of serum CKAP4 in ESCC. METHODS: This longitudinal study recruited 207 ESCC patients and age-/sex-matched healthy controls. Circulating levels of CKAP4 were measured using ELISA kits, while the expression of CKAP4 in esophageal tissue was evaluated using Western blotting. RESULTS: Serum CKAP4 levels were higher in ESCC patients (380.2±171.3 pg/mL) than healthy controls (271.8±97.4 pg/mL; P<0.001). The area under the receiver-operating characteristic curve of serum CKAP4 levels to identify the presence of ESCC was 0.675 (95% CI 0.622–0.728; P<0.001). According to Youden’s index, the best cutoff value was 429.1 pg/mL (sensitivity 0.415 and specificity 0.995). Furthermore, after follow-up, multivariate analyses identified that pathological lymph node metastases were the poorest prognostic factor (HR 1.862, 95% CI 1.093–3.173; P=0.022), followed by serum CKAP4 (HR 1.437, 95% CI 1.025–2.014; P=0.035). When stratified by tertiles of serum CKAP4, subjects in the first tertile presented a mean survival time of 75.4 months (95% CI 68.0–81.9), which decreased significantly in the second tertile (73.8 months, 95% CI 61.4–86.3) and the third tertile (59.9 months, 95% CI 49.8–70.0, log-rank χ(2)=8.235; P=0.016). CONCLUSION: These results suggested that serum CKAP4 could be a potential biomarker for clinical management of ESCC.