Hypermethylation of the CDKN2/p16 promoter during neoplastic progression in Barrett's esophagus.
OBJECTIVE
Inactivation of the CDKN2/p16(INK4A) tumor-suppressor gene is one of the most frequent genetic alterations in human malignancies. In esophageal adenocarcinomas, mutations of the p16 gene or homozygous deletions of the gene locus 9p21 are rare. This study investigated whether p16 promoter hypermethylation is an alternative mechanism for p16 gene inactivation during neoplastic progression in Barrett's esophagus.


METHODS
A methylation-specific polymerase chain reaction protocol was applied. A total of 95 specimens from 14 patients with Barrett's esophagus were analyzed longitudinally. The p16 promoter status was compared with histomorphological findings.


RESULTS
p16 promoter hypermethylation was detected in 9 of the 10 patients who had displayed dysplasia at some time during surveillance, whereas none of the patients who had not displayed dysplasia during surveillance had p16 promoter hypermethylation. p16 promoter hypermethylation was detected in 3% (2 of 67) of the samples without dysplasia, 60% (3 of 5) of the samples with lesions indefinite for dysplasia, 55.6% (10 of 18) of the specimens with low-grade dysplasia, and 75% (3 of 4) of the specimens with high-grade dysplasia.


CONCLUSIONS
These data suggest that p16 promoter hypermethylation is a common mechanism of p16 gene inactivation during neoplastic progression in Barrett's esophagus.
Klump
B
B
Department of Medicine I, University Hospital of Tübingen, T ubingen, Germany. bodo.klump@uni-tuebin
Hsieh
C J
CJ
Holzmann
K
K
Gregor
M
M
Porschen
R
R
D001471:Barrett Esophagus / Q000235:genetics*; D019175:DNA Methylation; D018450:Disease Progression; D019942:Genes, p16 / Q000235:genetics*; D006801:Humans; D008137:Longitudinal Studies; D008875:Middle Aged; D011230:Precancerous Conditions / Q000235:genetics