Research ArticleResearch Article

Detection of Frameshift Mutations of the Transforming Growth Factor β Receptor II in Gastric Cancers with Microsatellite Instability

Dong Wang, Xin Geng, Yanyun Li, Yuchuan Wang, Yanni Li, Linsheng Zhao and Weiming Zhang
Chinese Journal of Clinical Oncology August 2006, 3 (4) 267-272;

Article Figures & Data

Figures

  • Fig. 1.
    Fig. 1.

    Detection of microsatellite instability (MSI) with five markers in normal gastric tissue and gastric cancer. Arrows show abnormal bands of MSI. T: tumor; N: normal mucosa.

  • Fig. 2.
    Fig. 2.

    Detection of FMs of TGF βR II in normal gastric tissue and gastric cancer samples. The arrow indicates the abnormal bond of FM. T: tumor, N: normal gastric mucosa.

  • Fig. 3.
    Fig. 3.

    Methylation-specific PCR of the hMLHl promoter region in gastric cancers, precancerous lesions and normal gastric tissue. Bisulfite-treated DNA was amplified with methylated and unmethylated specific hMLHl primers. The 124-bp product is indicative of an unmethylated hMLHl allele, whereas the 196-bp product indicates a methylated hMLHl allele. T and N respectively show products amplified from the gastric cancers and normal gastric mucosa tissue. MP and UMP stand for products amplified using specific methylated and unmethylated primers.

  • Fig. (4A).
    Fig. (4A).

    Sequencing histograms (matching GenBank accession No. U26559) of the entire methylated hMLH1 promoter region amplified with sodium bisulfite-treated genomic DNAs from a primary gastric carcinoma. (4B) The sequencing result of methylated hMLH1 compares with the original hMLHl sequence in the NCBI Blast bank. Black arrows show that methylated CpG sites still appear as CpG, while white arrows show that unmethylated simple cytosines appear as thymines in the final sequence.

Tables

  • Table 1.

    Incidence of MSI, MMLH1 mtthylation and expression(frequency)

    GroupSample No.MSIMSI-HhMLHl methylationReduced hMLHl expression
    Gastric cancer4122 (53.7%)8(19.5%)17(41.5%)16(39.0%)
    Normal control600 (0.0%)0 (0.0%)0 (0%)1 (1.7%)
    P value-<0.05<0.05<0.05<0.05
  • Table 2.

    Incidence of TβR II mutation, hMLH1 mthhylatton and expression in 3 different groups frequency)

    GroupSample No.TβR II mutationhMLHl methylationReduced hMLHl expression
    MSS790 (0%)0 (0%)1 (1.3%)
    MSI-L140 (0%)a9 (64.2%)c8(57.1%)c
    MSI-H85 (62.5%)b8 (100%)b8 (100%)b
    Total1015 (4.9%)17(18.8%)17(18.8%)

    • ↵aP>0.05,MSI-L group vs. MSS group;

    • ↵bP<0.05, MSI-H group vs MSS group;

    • ↵cP<0.05, MSI--L group MS MSS group.

  • Table 3.

    Incidence of TβR II mutation, hMLH1 expression in 3 different hMLH1 methylated groups (frequency)

    hMLHl methylationSample No.TβR II mutationReduced hMLHl expressionMSIMSI-H
    Positive175 (29.4%)16(94.1%)17(100%)8(47.1%)
    Negative840 (0%)1 (1.2%)5 (6.0%)0 (0%)
    P value-<0.05<0.05<0.05<0.05
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