TY - JOUR
T1 - DNA hypermethylation on multiple CpG islands associated with increased DNA methyltransferase DNMT1 protein expression during multistage urothelial carcinogenesis
AU - Nakagawa, Tohru
AU - Kanai, Yae
AU - Ushijima, Saori
AU - Kitamura, Tadaichi
AU - Kakizoe, Tadao
AU - Hirohashi, Setsuo
N1 - Funding Information:
Supported by a Grant-in-Aid for the Second Term Comprehensive 10-Year Strategy for Cancer Control and a Grant-in-Aid for Cancer Research, Ministry of Health, Labor and Welfare of Japan, and a Research Resident Fellowship from the Foundation for Promotion of Cancer Research in Japan (TN).
PY - 2005/5
Y1 - 2005/5
N2 - Purpose: We elucidated the significance of aberrant DNA methylation on multiple CpG islands and its correlation with DNA methyltransferase DNMT1 protein expression during urothelial carcinogenesis. Materials and Methods: We examined the DNA methylation status on multiple CpG islands by methylation specific polymerase chain reaction and combined bisulfite restriction enzyme analysis in 12 specimens of normal urothelium, 23 of noncancerous urothelium showing no remarkable histological changes obtained from patients with bladder cancer (NBC) and 70 of transitional cell carcinoma (TCC). Results: DNA methylation on CpG islands of the p16 (0%, 17% and 21%) and death-associated protein kinase (13%, 33% and 29%) genes, and methylated in tumor-2 (56%, 60% and 76%), 12 (0%, 6% and 30%), 25 (25%, 27% and 35%) and 31 (45%, 56% and 79%) clones was detected in normal urothelium, NBCs and TCCs, respectively. The incidence of concurrent DNA hypermethylation on 3 or more CpG islands in NBCs (38%) was significantly higher than that in normal urothelium (0%, p = 0.0455) and even higher in TCCs (59%, p = 0.0043). The incidence of the CpG island methylator phenotype in nonpapillary carcinomas (nodular invasive carcinomas and their precursors, ie flat carcinoma in situ, 71%) was significantly higher than in papillary carcinomas (40%, p = 0.0143). In all specimens examined concurrent DNA hypermethylation on 3 or more CpG islands significantly correlated with immunohistochemically evaluated DNMT1 protein over expression (p = 0.0167). Conclusions: DNA hypermethylation on multiple CpG islands in association with DNMT1 protein over expression may participate in multistage urothelial carcinogenesis even at the precancerous stage and particularly in the development of nodular invasive carcinomas of the bladder.
AB - Purpose: We elucidated the significance of aberrant DNA methylation on multiple CpG islands and its correlation with DNA methyltransferase DNMT1 protein expression during urothelial carcinogenesis. Materials and Methods: We examined the DNA methylation status on multiple CpG islands by methylation specific polymerase chain reaction and combined bisulfite restriction enzyme analysis in 12 specimens of normal urothelium, 23 of noncancerous urothelium showing no remarkable histological changes obtained from patients with bladder cancer (NBC) and 70 of transitional cell carcinoma (TCC). Results: DNA methylation on CpG islands of the p16 (0%, 17% and 21%) and death-associated protein kinase (13%, 33% and 29%) genes, and methylated in tumor-2 (56%, 60% and 76%), 12 (0%, 6% and 30%), 25 (25%, 27% and 35%) and 31 (45%, 56% and 79%) clones was detected in normal urothelium, NBCs and TCCs, respectively. The incidence of concurrent DNA hypermethylation on 3 or more CpG islands in NBCs (38%) was significantly higher than that in normal urothelium (0%, p = 0.0455) and even higher in TCCs (59%, p = 0.0043). The incidence of the CpG island methylator phenotype in nonpapillary carcinomas (nodular invasive carcinomas and their precursors, ie flat carcinoma in situ, 71%) was significantly higher than in papillary carcinomas (40%, p = 0.0143). In all specimens examined concurrent DNA hypermethylation on 3 or more CpG islands significantly correlated with immunohistochemically evaluated DNMT1 protein over expression (p = 0.0167). Conclusions: DNA hypermethylation on multiple CpG islands in association with DNMT1 protein over expression may participate in multistage urothelial carcinogenesis even at the precancerous stage and particularly in the development of nodular invasive carcinomas of the bladder.
KW - Bladder
KW - Carcinoma, transitional cell
KW - CpG islands
KW - DNA
KW - Phenotype
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U2 - 10.1097/01.ju.0000154632.11824.4d
DO - 10.1097/01.ju.0000154632.11824.4d
M3 - Article
C2 - 15821584
AN - SCOPUS:17144413410
VL - 173
SP - 1767
EP - 1771
JO - Investigative Urology
JF - Investigative Urology
SN - 0022-5347
IS - 5
ER -