Increased NDRG1 expression is associated with advanced T stages and poor vascularization in non-small cell lung cancer

Abstract

N-myc downstream regulated gene 1 (NDRG1) is a member of the N-myc downstream regulated gene family which belongs to the alpha/beta hydrolase superfamily. Earlier studies have shown its association with inhibition of tumor metastasis. However, its function in malignant tumors is not fully enunciated. Recently there was increasing evidence that NDRG1 is involved in stress responses. In the current study, we examined the expression of NDRG1 and its correlation with clinicopathological factors and microvessel density (MVD) in non-small cell lung cancer (NSCLC) using immunohistochemistry (IHC). NDRG1 expression in NSCLC (71/115, 61.7%) was higher than that in normal lung tissues (32/115, 27.8%) (p < 0.05). NDRG1 expression in NSCLC cells was found in cytoplasm (63/115, 54.8%), nuclear (24/115, 20.9%) and cell membrane (13/115, 11.3%). NDRG1 expression in NSCLC with advanced T stages (T2-4) (63/84, 75.0%) was significantly higher than that with T1 stage (8/31, 25.8%) (P < 0.05). No other clinicopathological factors including lymph node metastasis were found to be associated with NDRG1 expression (p > 0.05). Moreover increased NDRG1 expression was associated with lower MVD in NSCLC (P < 0.05). MVD in adenocarcinoma (33.4 ± 8.4/HP) was significantly higher than that in squamous cell carcinoma (SCC) (19.3 ± 8.1/HP) (P < 0.05). No other clinicopathological factors were associated with MVD in NSCLC (p > 0.05). The present findings indicate an increase of NDRG1 expression with the progress of tumour extent which may be due to unbalanced tumor oxygenation on account of poor vascularization in NSCLC.