RESUMO
BACKGROUND/AIM: We evaluated the predictive value of candidate serum biomarkers for recurrence in stage II and III colorectal cancer (CRC) after curative surgery. PATIENTS AND METHODS: A total of 33 and 120 patients with CRC with or without recurrence at 5 years after curative surgery were included in the training set and the validation set, respectively. Possible serum biomarkers were examined for associations with CRC recurrence using receiver operating characteristics (ROC) curve analysis. RESULTS: In the training set, the expression levels of the 14 biomarkers were compared according to recurrence. Among them, five biomarkers that had significantly different expression levels were validated in 60 patients with recurrence at 5 years after curative surgery and 60 patients without. Multivariate analysis showed that natural log-transformed values of carcinoembryonic antigen (CEA), cyclin-dependent kinase regulatory subunit 2 (CKS2), 2'-5'-oligoadenylate synthetase 2 (OAS2), and autophagy-related gene 5 (ATG5) in preoperative serum were significantly related to recurrence. ROC analysis showed that these biomarkers were able to discriminate patients with recurrence from those without (area under the curve=0.828, 95% confidence interval=0.755-0.990). CONCLUSION: Preoperative serum levels of CEA, CKS2, OAS2 and ATG5 were independent risk factors for recurrence. A combination of serum CEA, CKS2, OAS2 and ATG5 predicted tumor recurrence well in patients with stage II and III CRC.