Aberrant promoter methylation of multiple genes during pathogenesis of bladder cancer.
OBJECTIVE
The aims of our study were to elucidate the role of methylation of a large panel of genes during multistage pathogenesis of bladder cancer and to correlate our findings with patient age and other clinicopathologic features.


METHODS
We studied the methylation status of 21 genes by quantitative methylation-specific PCR in an evaluation set of 25 tumor and 5 normal samples. Based on methylation frequency in tumors and normals in gene evaluation set, we selected 7 candidate genes and tested an independent set of 93 tumors and 26 normals. The presence or absence of methylation was evaluated for an association with cancer using cross-tabulations and chi(2) or Fisher's exact tests as appropriate. All statistical tests were two-sided.


RESULTS
Most primary tumors (89 of 93, 96%) had methylation of one or more genes of independent set; 53 (57%) CCNA1, 29 (31%) MINT1, 36 (39%) CRBP, 53 (57%) CCND2, 66 (71%) PGP9.5, 60 (65%) CALCA, and 78 (84%) AIM1. Normal uroepithelium samples from 26 controls revealed no methylation of the CCNA1 and MINT1 genes, whereas methylation of CRBP, CCND2, PGP9.5, and CALCA was detected at low levels. All the 7 genes in independent set were tightly correlated with each other and 3 of these genes showed increased methylation frequencies in bladder cancer with increasing age. PGP9.5 and AIM1 methylation correlated with primary tumor invasion.


CONCLUSIONS
Our results indicate that the methylation profile of novel genes in bladder cancers correlates with clinicopathologic features of poor prognosis and is an age-related phenomenon.
Department of Otolaryngology-Head and Neck Surgery, The Johns Hopkins University School of Medicine, 1550 Orleans Street, CRB II, 5M, Baltimore, MD 21231, USA.
Mariana
M
Brait
Shahnaz
S
Begum
André L
AL
Carvalho
Santanu
S
Dasgupta
André L
AL
Vettore
Bogdan
B
Czerniak
Otávia L
OL
Caballero
William H
WH
Westra
David
D
Sidransky
Mohammad Obaidul
MO
Hoque
D000368:Aged; D000704:Analysis of Variance; D014408:Biomarkers, Tumor / Q000235:genetics*; D016009:Chi-Square Distribution; D019175:DNA Methylation; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016133:Polymerase Chain Reaction / Q000379:methods; D016016:Proportional Hazards Models; D001749:Urinary Bladder Neoplasms / Q000235:genetics*
D014408:Biomarkers, Tumor