title: Aberrant methylation of the 8p22 tumor suppressor gene DLC1 in renal cell carcinoma.
abstract: Epigenetic mechanisms involving DNA methylation and chromatin remodeling are important in silencing tumor suppressor genes (TSG) in various malignancies, including renal cell carcinoma (RCC). DLC1 (deleted in liver cancer 1)/ARHGAP7 is a recently identified 8p22 candidate TSG. Frequent methylation of the DLC1 promoter with resultant gene silencing has been reported in several tumors, but not in RCC yet. We examined DLC1 promoter methylation in 34 primary RCCs and the corresponding non-malignant tissues, and the correlation of DLC1 methylation with the clinicopathological characteristics of RCC patients. Although DLC1 methylation and downregulation were only detected in one of seven RCC cell lines using methylation-specific PCR (MSP) and semi-quantitative reverse-transcription PCR, we found that the DLC1 promoter was methylated in 35% (12/34) of primary RCC tumors, which was further confirmed by direct sequencing of MSP products and high-resolution bisulfite genomic sequencing. In contrast, only one of the 34 (3%) non-malignant renal tissues had weak methylation. Aberrant DLC1 methylation appeared to be a relatively early event during renal tumorigenesis since 33% of the RCC tumors with pT1 (TNM staging) showed methylation, which is similar to other late stage tumors. Thus, our results demonstrated that DLC1 methylation occurs in a subset of RCC tumors and may play a role in renal carcinogenesis.
authors.affiliation: Department of Urology, Peking University First Hospital and Institute of Urology, Peking University, Beijing, China.
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhang
authors.forename: Jianming
authors.initials: J
authors.lastname: Ying
authors.forename: Kai
authors.initials: K
authors.lastname: Zhang
authors.forename: Hongyu
authors.initials: H
authors.lastname: Li
authors.forename: Ka Man
authors.initials: KM
authors.lastname: Ng
authors.forename: Yayuan
authors.initials: Y
authors.lastname: Zhao
authors.forename: Qun
authors.initials: Q
authors.lastname: He
authors.forename: Xinyu
authors.initials: X
authors.lastname: Yang
authors.forename: Dianqi
authors.initials: D
authors.lastname: Xin
authors.forename: Shuen-Kuei
authors.initials: SK
authors.lastname: Liao
authors.forename: Qian
authors.initials: Q
authors.lastname: Tao
authors.forename: Jie
authors.initials: J
authors.lastname: Jin
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000235:genetics; D002292:Carcinoma, Renal Cell / Q000235:genetics*; D045744:Cell Line, Tumor; D019175:DNA Methylation; D005260:Female; D020690:GTPase-Activating Proteins; D006801:Humans; D008297:Male; D008875:Middle Aged; D025521:Tumor Suppressor Proteins / Q000235:genetics*
chemical_list: D014408:Biomarkers, Tumor; C112352:DLC1 protein, human; D020690:GTPase-Activating Proteins; D025521:Tumor Suppressor Proteins