Mutations of the human E-cadherin (CDH1) gene

Area of Science:

• Oncology
• Molecular Biology
• Genetics

Background:

• E-cadherin is a cell-cell adhesion molecule crucial for suppressing tumor invasion.
• Inactivating mutations in the E-cadherin gene (CDH1) are prevalent in diffuse gastric and lobular breast cancers.
• CDH1 mutations are identified early in tumorigenesis, indicating a tumor suppressor role.

Purpose of the Study:

• To analyze the spectrum and types of CDH1 mutations in diffuse gastric and lobular breast cancers.
• To investigate the differences in mutation types between these cancer types.
• To confirm the tumor suppressor function of E-cadherin in specific cancers.

Main Methods:

• Analysis of reported somatic mutations in the CDH1 gene.
• Categorization of mutations based on type (missense, splice site, truncation, insertions, deletions, nonsense).
• Comparison of mutation profiles between diffuse gastric and lobular breast cancers.

Main Results:

• 69 somatic CDH1 mutations were reported, including splice site and truncation mutations.
• Diffuse gastric cancers show predominantly exon skipping (in-frame deletions).
• Lobular breast cancers exhibit mainly out-of-frame mutations, leading to truncated E-cadherin fragments, often with loss of heterozygosity.

Conclusions:

• E-cadherin functions as a tumor suppressor in diffuse gastric and lobular breast cancers.
• Distinct mutation types in CDH1 between these cancers suggest different mechanisms of E-cadherin inactivation.
• Germline CDH1 mutations are associated with early-onset gastric cancer, reinforcing its tumor suppressor role.