Neutrophil gelatinase-associated lipocalin and its receptor: independent prognostic factors of oesophageal squamous cell carcinoma

Aim Previous studies have shown that neutrophil gelatinase-associated lipocalin (NGAL) is overexpressed in oesophageal squamous cell carcinoma (ESCC) and closely associated with the invasiveness of ESCC cells. Recently, NGAL receptor (NGALR) was identified from ESCC cells, and was also found to be increased in ESCC. The purpose of this study was to reveal the clinical significance of NGAL and/or NGALR in ESCC. Methods Tissue microarray was performed to detect expression of NGAL and NGALR in 222 ESCC specimens. Pearson x(2) test was used to analyse correlations between NGAL and/or NGALR expression and clinicopathological features. Kaplane-Meier survival curves and the Cox proportional hazards regression model were used to evaluate the effect of NGAL and/or NGALR expression on prognosis of patients with ESCC. Results NGAL and NGALR were highly expressed in ESCC. c 2 test results showed no significant correlations between NGAL or NGALR expression and clinicopathological features. However, NGAL/NGALR coexpression correlated with histological differentiation grade (p = 0.033). Survival analysis showed that positive expression of NGAL or NGALR was significantly associated with a poor prognosis for patients with ESCC (p = 0.000 or p = 0.002). Patients with positive expression of both NGAL and NGALR had a shorter survival time than those with negative expression of both (p = 0.048). Multivariate analysis showed that both NGAL and NGALR were independent prognostic factors. Conclusion These results indicate that both NGAL and NGALR may be involved in the progression of ESCC and can be considered as independent prognostic factors of ESCC.