Clinical significance of neutrophil gelatinase-associated lipocalin (NGAL) in colorectal cancer: a meta-analysis renewal

Background and objectives: More observational studies from different parts of the world have been executed to demonstrate the molecular biological relationship between NGAL and colorectal cancer. Our previous study in 2014 has extracted data from 5 studies with literature screening until early 2013. This meta-analysis aimed to recruit more recent papers and explore the overall accuracy of NGAL detection on diagnosis. Materials and methods: We divided this meta-analysis into two layers: 1. distinguishing adenocarcinoma from other abnormalities and normal tissue; 2. distinguishing adenocarcinoma and abnormalities with high possibility of carcinogenesis from benign hyperplasia and normal tissue Results: For Layer 1, the pooled sensitivity and specificity of all studies were 0.81 (95% CI, 0.78-0.84) and 0.56 (95% CI, 0.52-0.60). The pooled positive likelihood ratio and negative likelihood ratio were 2.29 (95% CI, 1.40-3.74) and 0.34 (95% CI, 0.18-0.63). The pooled diagnostic odds ratios was 11.29 (95% CI, 3.36-38.01). The area under the summary receiver operating characteristic curve for the diagnosis of colorectal cancer was 0.8476. For Layer 2, the pooled sensitivity and specificity of all studies were 0.76 (95% CI, 0.73-0.79) and 0.63 (95% CI, 0.58-0.67). The pooled positive likelihood ratio and negative likelihood ratio were 7.11 (95% CI, 1.97-25.63) and 0.35 (95% CI, 0.23-0.54). The pooled diagnostic odds ratios was 23.10 (95% CI, 6.55-81.44). The area under the summary receiver operating characteristic curve for the diagnosis of colorectal cancer was 0.8900. Conclusion: NGAL is more suitable for screening adenocarcinoma and abnormalities with high possibility of carcinogenesis from benign hyperplasia and normal tissue.