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

Growing evidence has implicated that neutrophil gelatinase-associated lipocalin (NGAL) plays a role in a spectrum of human cancers. Several observational studies from different parts of the world have been devoted to elucidate the clinical relationship between NGAL and colorectal cancer. This meta-analysis aimed to explore the overall accuracy of NGAL detection for the diagnosis and prognosis of colorectal cancer. Based on comprehensive literature screening on Pubmed, Ovid, and CNKI databases, our screening covered all published papers until March 2013. The relevant papers were selected according to some stringent inclusion criteria. Essential data were extracted from the recruited papers and further processed by systematic meta-analysis. The meta-analysis included 5 studies for diagnosis of colorectal cancer. Overall, the pooled sensitivity and specificity of all studies were 73% (95% CI = 0.69-0.76) and 89% (95% CI = 0.85-0.93). The pooled positive likelihood ratio and negative likelihood ratio were 5.41 (95% CI = 3.85-7.59) and 0.37 (95% CI = 0.22-0.62). The pooled diagnostic odds ratios was 18.05 (95% CI = 11.77-27.69). The area under the summary receiver operating characteristic curve for the diagnosis of colorectal cancer was 0.87. Meanwhile, 3 studies were included to evaluate the prognostic significance of NGAL overexpression in colorectal cancer patients. The pooled hazard ratio was 2.12 (95% CI = 1.35-3.33). High level of NGAL predicted poor disease-free survival. Thus, NGAL is a potential biomarker for the diagnosis and prognosis of colorectal cancer.