Clinical significance of the detection of serum neutrophil gelatinase-associated lipocalin in human colorectal cancer

Abstract

To explore the feasibility and clinical significance of the detection of serum neutrophil gelatinase-associated lipocalin (NGAL) in human colorectal cancer. Levels of NGAL in serum samples from 133 healthy people, 125 colorectal polyps patients and 100 colorectal cancer patients respectively were determined by sandwich ELISA assay. Relationship of NGAL level with clinicopathological features of colorectal cancer patients was analyzed. The optimal cut-off value of serum NGAL for diagnosing colorectal cancer was determined by ROC curve and compared with CEA and CA19-9. Univariate and multivariate analyses were performed to examine the relationship of NGAL level with the prognosis of patients with colorectal cancer. The median serum NGAL protein level in 100 colorectal cancer cases was 67.96 (53.30-79.86) μg/L, significantly higher than that in healthy people and colorectal polyps patients. The differences were statistically significant (all P<0.01). Serum NGAL protein level was significantly associated with tumor diameter, TNM stage, lymph node metastasis and vascular involvement (P<0.05). The optimal cut-off point of serum NGAL protein level for diagnosing colorectal cancer was 49.78 μg/L, and the sensitivity and specificity were 88% and 81% respectively. As for colorectal cancer patients with stage I, the sensitivity of serum NGAL (78.9%) was significantly higher as compared to CA19-9 (31.6%) and CEA (36.8%); as for those with stage II, the sensitivity of serum NGAL(88.0%) was also significantly higher compared to CA19-9 (48.0%) and CEA (52.0%). Kaplan-Meier analysis showed that patients with positive NGAL (≥49.78 μg/L) had worse survival than those with negative NGAL (P=0.002). Multivariate analysis showed that NGAL was an independent prognostic factor (HR=2.060, 95%CI:1.023-4.150, P=0.043). NGAL can be served as the novel malignant biological phenotype marker for human colorectal cancer and can be used for the risk stratification. NGAL may be an independent prognostic factor in colorectal cancer.