title: Regional DNA hypermethylation and DNA methyltransferase (DNMT) 1 protein overexpression in both renal tumors and corresponding nontumorous renal tissues.
abstract: To evaluate the significance of altered DNA methylation during renal tumorigenesis, tumorous tissues (T) and corresponding nontumorous renal tissues (N) from 94 patients with renal tumors, and normal renal tissues (C) from 16 patients without renal tumors were investigated. DNA methylation status on CpG islands of the p16, human MutL homologue 1 (hMLH1), von-Hippel Lindau (VHL) and thrombospondin-1 (THBS-1) genes and the methylated in tumor (MINT) -1, -2, -12, -25 and -31 clones and DNA methyltransferase (DNMT) 1 expression were examined by bisulfite modification and immunohistochemistry, respectively. The average number of methylated CpG islands was significantly higher in N than in C, and was even higher in T. The average number of methylated CpG islands in N was significantly correlated with a higher histological grade of corresponding conventional renal cell carcinomas (RCCs). The average number of methylated CpG islands in RCCs was significantly correlated with macroscopic configuration with extranodular or multinodular growth, higher histological grade, infiltrating growth pattern and vascular involvement. The recurrence-free survival rate of patients with RCCs showing accumulation of DNA methylation was significantly lower than that of patients not showing this feature. The incidence of nuclear immunoreactivity for DNMT1 tended to be higher in proximal tubules from N than in those from C, and was significantly higher in RCCs. From the viewpoint of altered DNA methylation, N is at the precancerous stage, and N showing accumulation of DNA methylation may generate more malignant RCCs. Regional DNA hypermethylation may be associated with renal tumorigenesis from a precancerous condition to malignant progression and become a predictor of patient prognosis.
authors.affiliation: Pathology Division, National Cancer Center Research Institute, Tokyo, Japan.
authors.forename: Eri
authors.initials: E
authors.lastname: Arai
authors.forename: Yae
authors.initials: Y
authors.lastname: Kanai
authors.forename: Saori
authors.initials: S
authors.lastname: Ushijima
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Fujimoto
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Mukai
authors.forename: Setsuo
authors.initials: S
authors.lastname: Hirohashi
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002352:Carrier Proteins / Q000235:genetics; D018899:CpG Islands; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000235:genetics*; D019175:DNA Methylation; D005260:Female; D015971:Gene Expression Regulation, Enzymologic; D015972:Gene Expression Regulation, Neoplastic; D019942:Genes, p16; D006801:Humans; D007150:Immunohistochemistry; D007668:Kidney / Q000201:enzymology* / Q000378:metabolism; D007680:Kidney Neoplasms / Q000201:enzymology* / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D000070957:MutL Protein Homolog 1; D009687:Nuclear Proteins / Q000235:genetics; D016133:Polymerase Chain Reaction; D011237:Predictive Value of Tests; D011379:Prognosis; D019700:Thrombospondin 1 / Q000235:genetics; D015854:Up-Regulation; D051794:Von Hippel-Lindau Tumor Suppressor Protein / Q000235:genetics
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; C501486:MLH1 protein, human; D009687:Nuclear Proteins; D019700:Thrombospondin 1; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases; C000619380:DNMT1 protein, human; D051794:Von Hippel-Lindau Tumor Suppressor Protein; D000070957:MutL Protein Homolog 1; C497446:VHL protein, human