Decreased expression of NDRG1 is correlated with tumor progression and poor prognosis in patients with esophageal squamous cell carcinoma

NDRG1 (N-myc downstream regulated gene-1) was reported to be necessary for p53-mediated apoptosis and to be regulated by PTEN (phosphatase and tensin homolog). In several cancers, it was suggested to be a tumor suppressor gene. Its significance in esophageal squamous cell carcinoma (ESCC) has not been studied. The objective of this study was to clarify the relation between clinicopathological and biologic factors in esophageal carcinoma and to determine the prognostic significance of the expression of NDRG1. Expression of NDRG1 mRNA was quantified by real-time reverse transcription polymerase chain reaction using a Lightcycler in 47 esophageal ESCC specimens. The data were analyzed with reference to clinicopathological factors. Among the esophageal cancer tissues, NDRG1 mRNA expression was significantly lower in tumors of more advanced pathological stage (0-I vs. II-IV; P = 0.0027) and local tumor invasion (T1-2 vs. T3-4; P = 0.0136). Patients who had low NDRG1 mRNA expression had a significantly shorter survival after surgery compared with patients who had high NDRG1 mRNA expression (log-rank test, P = 0.0478). Impaired NDRG1 expression may lead to more aggressive invasion of ESCC.