title: Hypermethylation of the TSLC1 gene promoter in primary gastric cancers and gastric cancer cell lines.
abstract: The TSLC1 (tumor suppressor in lung cancer-1) gene is a novel tumor suppressor gene on chromosomal region 11q23.2, and is frequently inactivated by concordant promoter hypermethylation and loss of heterozygosity (LOH) in non-small cell lung cancer (NSCLC). Because LOH on 11q has also been observed frequently in other human neoplasms including gastric cancer, we investigated the promoter methylation status of TSLC1 in 10 gastric cancer cell lines and 97 primary gastric cancers, as well as the corresponding non-cancerous gastric tissues, by bisulfite-SSCP analysis followed by direct sequencing. Allelic status of the TSLC1 gene was also investigated in these cell lines and primary gastric cancers. The TSLC1 promoter was methylated in two gastric cancer cell lines, KATO-III and ECC10, and in 15 out of 97 (16%) primary gastric cancers. It was not methylated in non-cancerous gastric tissues, suggesting that this hypermethylation is a cancer-specific alteration. KATO-III and ECC10 cells retained two alleles of TSLC1, both of which showed hypermethylation, associated with complete loss of gene expression. Most of the primary gastric cancers with promoter methylation also retained heterozygosity at the TSLC1 locus on 11q23.2. These data indicate that bi-allelic hypermethylation of the TSLC1 promoter and resulting gene silencing occur in a subset of primary gastric cancers.
authors.affiliation: Department of Pathology, Yamagata University School of Medicine, Yamagata 990-9585, Japan.
authors.forename: Teiichiro
authors.initials: T
authors.lastname: Honda
authors.forename: Gen
authors.initials: G
authors.lastname: Tamura
authors.forename: Takayoshi
authors.initials: T
authors.lastname: Waki
authors.forename: Zhe
authors.initials: Z
authors.lastname: Jin
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Sato
authors.forename: Teiichi
authors.initials: T
authors.lastname: Motoyama
authors.forename: Sumio
authors.initials: S
authors.lastname: Kawata
authors.forename: Wataru
authors.initials: W
authors.lastname: Kimura
authors.forename: Satoshi
authors.initials: S
authors.lastname: Nishizuka
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Murakami
mesh_terms: D000328:Adult; D000483:Alleles; D001483:Base Sequence; D000075982:Cell Adhesion Molecule-1; D015815:Cell Adhesion Molecules; D019175:DNA Methylation; D005260:Female; D006579:Heterozygote; D006801:Humans; D007136:Immunoglobulins; D019656:Loss of Heterozygosity; D008297:Male; D008565:Membrane Proteins; D018895:Microsatellite Repeats; D008875:Middle Aged; D008969:Molecular Sequence Data; D018807:Polymorphism, Single-Stranded Conformational; D011401:Promoter Regions, Genetic; D011506:Proteins / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000235:genetics*; D014407:Tumor Cells, Cultured; D025521:Tumor Suppressor Proteins
chemical_list: C403514:CADM1 protein, human; D000075982:Cell Adhesion Molecule-1; D015815:Cell Adhesion Molecules; D007136:Immunoglobulins; D008565:Membrane Proteins; D011506:Proteins; D025521:Tumor Suppressor Proteins