Hypermethylation of the nel-like 1 gene is a common and early event and is associated with poor prognosis in early-stage esophageal adenocarcinoma

The nel-like1 ( NELL1) gene maps to chromosome 11p15, which frequently undergoes loss of heterozygosity in esophageal adenocarcinoma ( EAC). NELL1 promoter hypermethylation was examined by real-time methylation-specific polymerase chain reaction in 259 human esophageal tissues. Hypermethylation of this promoter showed highly discriminative receiver-operator characteristic curve pro. les, clearly distinguishing esophageal squamous cell carcinoma ( ESCC) and EAC from normal esophagus ( NE) ( P < 0.001). NELL1 normalized methylation values were significantly higher in Barrett's metaplasia ( BE), dysplastic Barrett's ( D) and EAC than in NE ( P < 0.0000001). NELL1 hypermethylation frequency was zero in NE but increased early during neoplastic progression, to 41.7% in BE from patients with Barrett's alone, 52.5% in D and 47.8% in EAC. There was a significantly correlation between NELL1 hypermethylation and BE segment length. Three ( 11.5%) of 26 ESCCs exhibited NELL1 hypermethylation. Survival correlated inversely with NELL1 hypermethylation in patients with stages I-II (P = 0.0264) but not in stages III-IV ( P = 0.68) EAC. Treatment of KYSE220 ESCC and BIC EAC cells with 5-aza-2'-deoxycytidine reduced NELL1 methylation and increased NELL1 mRNA expression. NELL1 mRNA levels in EACs with an unmethylated NELL1 promoter were significantly higher than those in EACs with a methylated promoter ( P 0.02). Promoter hypermethylation of NELL1 is a common, tissue-specific event in human EAC, occurs early during Barrett's-associated esophageal neoplastic progression, and is a potential biomarker of poor prognosis in early-stage EAC.