We investigated if the serum cytokeratin 19 fragment 21.1 (CYFRA21-1) level was elevated in nasopharyngeal carcinoma (NPC) and can function as a biomarker for detection and monitoring of NPC. Three hundred and one study subjects were divided into two groups: the NPC group (n=126) and healthy control group (n=175). Serum CYFRA21-1 levels were measured before and after treatment using a chemiluminescent immunoassay, and its association with tumor stage and the clinical objective responses were

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... lyzed. Receiver operating characteristic (ROC) curve analysis was performed to discriminate patients with NPC from the healthy controls. The pretreatment serum CYFRA21-1 level was significantly elevated in patients with NPC compared with the healthy controls (5.07±1.98 ng/ml vs 2.36±1.21 ng/ml, p<0.001), and it declined significantly after the entire treatment (2.14±0.72 ng/ml, p<0.001). The serum CYFRA21-1 level of patients with a classification of T3-4 was significantly higher than that of those with class T1-2 (5.64±2.23 ng/ml vs 4.62±1.64 ng/ml, p=0.006), and that of patients with clinical stage III-IV was higher than clinical stage I-II (5.31±2.02 vs 4.04±1.37 ng/ml, p=0.003). The AUC, sensitivity and specificity of elevated serum CYFRA21-1 in patients with NPC was 0.91, 0.83 and 0.89 respectively. In conclusion, the serum CYFRA21-1 level could be a reliable and effective biomarker for the detection and monitoring of NPC tumor progression.