title: Hypermethylation of the AKAP12 promoter is a biomarker of Barrett's-associated esophageal neoplastic progression.
abstract: The A-kinase anchoring protein 12 (AKAP12) is a kinase scaffold protein with known tumor suppressor activity. Recently, AKAP12 promoter hypermethylation was reported in gastric and colorectal cancers. We examined AKAP12 promoter hypermethylation using real-time methylation-specific PCR in 259 human esophageal tissues. AKAP12 hypermethylation showed highly discriminative receiver-operator characteristic (ROC) curve profiles, clearly distinguishing esophageal adenocarcinoma (EAC) from esophageal squamous cell carcinoma and normal esophagus (P < 0.0001). AKAP12-normalized methylation values were significantly higher in Barrett's metaplasia (BE), dysplastic Barrett's, and EAC than in normal esophagus (P < 0.0000001). AKAP12 hypermethylation frequency was zero in normal esophagus but increased early during neoplastic progression, to 38.9% in BE from patients with Barrett's alone, 52.5% in dysplastic Barrett's metaplasia, and 52.2% in EAC. AKAP12 hypermethylation levels were significantly higher in normal esophageal epithelia from patients with EAC (mean = 0.00082) than in normal esophagi from patients without Barrett's or esophageal cancer (mean = 0.00007; P = 0.006). There was a significant correlation between AKAP12 hypermethylation and BE segment length, a known clinical neoplastic progression risk factor. In contrast, only 2 (7.7%) of 26 esophageal squamous cell carcinomas exhibited AKAP12 hypermethylation. Treatment of BIC and OE33 EAC cells with 5-aza-2'-deoxycytidine reduced AKAP12 methylation and increased AKAP12 mRNA expression. AKAP12 mRNA levels in EACs with unmethylated AKAP12 (mean = 0.1663) were higher than in EACs with methylated AKAP12 (mean = 0.0668). We conclude that promoter hypermethylation of AKAP12 is a common, tissue-specific event in human EAC, occurs early during Barrett's-associated esophageal neoplastic progression, and is a potential biomarker for the early detection of EAC.
authors.affiliation: Division of Gastroenterology, Department of Medicine, Johns Hopkins University School of Medicine, 1503 East Jefferson Street, Baltimore, MD 21231, USA.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Jin
authors.forename: James P
authors.initials: JP
authors.lastname: Hamilton
authors.forename: Jian
authors.initials: J
authors.lastname: Yang
authors.forename: Yuriko
authors.initials: Y
authors.lastname: Mori
authors.forename: Alexandru
authors.initials: A
authors.lastname: Olaru
authors.forename: Fumiaki
authors.initials: F
authors.lastname: Sato
authors.forename: Tetsuo
authors.initials: T
authors.lastname: Ito
authors.forename: Takatsugu
authors.initials: T
authors.lastname: Kan
authors.forename: Yulan
authors.initials: Y
authors.lastname: Cheng
authors.forename: Bogdan
authors.initials: B
authors.lastname: Paun
authors.forename: Stefan
authors.initials: S
authors.lastname: David
authors.forename: David G
authors.initials: DG
authors.lastname: Beer
authors.forename: Rachana
authors.initials: R
authors.lastname: Agarwal
authors.forename: John M
authors.initials: JM
authors.lastname: Abraham
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: Meltzer
mesh_terms: D054758:A Kinase Anchor Proteins / Q000235:genetics* / Q000378:metabolism; D000230:Adenocarcinoma / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D001471:Barrett Esophagus / Q000235:genetics* / Q000473:pathology; D014408:Biomarkers, Tumor / Q000235:genetics* / Q000378:metabolism; D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D016022:Case-Control Studies; D018797:Cell Cycle Proteins / Q000235:genetics* / Q000378:metabolism; D002471:Cell Transformation, Neoplastic; D019175:DNA Methylation; D018450:Disease Progression; D004938:Esophageal Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D011401:Promoter Regions, Genetic / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D014407:Tumor Cells, Cultured
chemical_list: D054758:A Kinase Anchor Proteins; C491162:AKAP12 protein, human; D014408:Biomarkers, Tumor; D018797:Cell Cycle Proteins; D012333:RNA, Messenger