Prognostic analysis of E-cadherin gene promoter hypermethylation in patients with surgically resected, node-positive, diffuse gastric cancer.
OBJECTIVE
Recent investigations have demonstrated that hypermethylation is a frequent mechanism for silencing tumor suppressor genes. This is a potentially reversible epigenetic change, and it is the target of a novel class of anticancer compounds with demethylating activity. Better understanding of the clinical implications of hypermethylation will allow the optimal planning of future trials with demethylating drugs. In this perspective, we investigated whether hypermethylation in the CDH1 promoter region is correlated with poor prognosis of patients with surgically resected, node-positive, diffuse gastric cancer.


METHODS
Consecutive cases of diffuse gastric cancer were considered eligible for study entry. Additional inclusion criteria were radical surgery with a minimum of D1 lymphadenectomy, complete follow-up information, and availability of tumor specimens for methylation-specific PCR and immunohistochemistry analyses.


RESULTS
CDH1 promoter hypermethylation was found in 40 of 73 cases (54%), and it was significantly associated with worse prognosis. In patients with and without hypermethylation, the 5-year event-free survival rate was 30% and 62%, respectively, and the 5-year overall survival rate was 35% and 67%, respectively. CDH1 promoter hypermethylation retained its prognostic role for disease-free survival (P < 0.001) and overall survival (P < 0.001) in multivariate analysis. Immunohistochemistry showed a significant association between CDH1 methylation and E-cadherin expression (P < 0.001).


CONCLUSIONS
This study shows adverse prognostic effect of CDH1 promoter hypermethylation in patients with diffuse gastric cancer. This form of cancer, and other types with frequent hypermethylation and silencing of critical tumor suppressor genes, would make appropriate targets for the testing of novel compounds with demethylating activity.
Graziano
Francesco
F
Medical Oncology Unit, Hospital of Urbino, Urbino, Italy. frada@tin.it
Arduini
Federica
F
Ruzzo
Annamaria
A
Bearzi
Italo
I
Humar
Bostjan
B
More
Helen
H
Silva
Rosarita
R
Muretto
Pietro
P
Guilford
Parry
P
Testa
Enrica
E
Mari
Davide
D
Magnani
Mauro
M
Cascinu
Stefano
S
D000328:Adult; D015820:Cadherins / Q000096:biosynthesis* / Q000235:genetics*; D019175:DNA Methylation; D017931:DNA Primers / Q000737:chemistry; D018572:Disease-Free Survival; D005260:Female; D016147:Genes, Tumor Suppressor; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction; D011379:Prognosis; D011401:Promoter Regions, Genetic; D016016:Proportional Hazards Models; D013274:Stomach Neoplasms / Q000175:diagnosis* / Q000235:genetics* / Q000473:pathology; D013997:Time Factors
D015820:Cadherins; D017931:DNA Primers