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[Human mismatch repair genes and HNPCC]
1Department of Hygiene and Oncology, Tokyo Medical and Dental University School of Medicine.
Nihon Rinsho. Japanese Journal of Clinical Medicine
|April 1, 1996
Summary
Hereditary nonpolyposis colorectal cancer (HNPCC) is linked to DNA repair gene mutations. Genomic instability in HNPCC tumors targets the TGF-beta type II receptor gene, impacting cancer development.
Area of Science:
- Genetics
- Molecular Biology
- Oncology
Context:
- Hereditary nonpolyposis colorectal cancer (HNPCC) is a significant inherited cancer susceptibility syndrome.
- Mutations in DNA mismatch repair genes (e.g., hMSH2, hMLH1) are established causes of HNPCC.
- Germline mutations in hMSH2 and hMLH1 were identified in Japanese and Korean HNPCC families.
Purpose:
- To investigate the role of the TGF-beta type II receptor gene mutation in the genomic instability observed during HNPCC tumorigenesis.
- To establish a basis for the presymptomatic diagnosis of HNPCC patients.
Summary:
- Screening of tumor DNA from HNPCC patients revealed that 71% of genomic instability-positive tumors (17 out of 24) had A deletions in the (A)10 repeat of the TGF-beta type II receptor gene.
- None of the genomic instability-negative tumors exhibited these deletions.
- These deletions lead to frameshift mutations, inactivating the receptor and causing protein truncation.
Impact:
- The findings indicate that the TGF-beta type II receptor gene is a primary target of genomic instability in HNPCC tumorigenesis.
- This research provides crucial insights into the molecular mechanisms underlying HNPCC.
- Identifies potential targets for diagnostic and therapeutic strategies in HNPCC.