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PTEN/MMAC1 expression in esophageal squamous cell carcinomas
1Department of Surgery and Surgical Basic Science, Graduate School of Medicine, Kyoto University, Sakyoku, Kyoto 606-8507, Japan.
Abstract:
The PTEN/MMAC1 gene at 10q23.3 is a novel tumor suppressor gene candidate. Various kinds of tumors have mutations in this gene. However, in some cancers PTEN/MMAC1 gene may be inactivated by mechanisms other than gene deletion and mutation, including promoter methylation or translational modification. The aim of this study was to determine whether there are abnormalities in the expression of PTEN/MMAC1 gene in esophageal cancer. Reverse transcription polymerase chain reaction and western blot were used to examine PTEN/MMAC1 expression in human esophageal squamous cell lines and normal cultured esophageal epithelial cells. Immunohistochemical staining was carried out to detect PTEN/MMAC1 expression in surgically resected esophageal squamous cell carcinomas and normal esophageal epithelium. All 30 esophageal cancer cell lines (KYSE series) and normal cultured esophageal epithelial cells expressed PTEN/MMAC1 mRNA. Western blot analysis confirmed that all the cell lines expressed PTEN/MMAC1 protein and there was no difference in expression level. Immunohistochemical study showed that the PTEN/MMAC1 protein was localized dominantly in the cytoplasm and strongly stained in all 42 surgically resected esophageal squamous cell carcinomas and normal esophageal epithelium. PTEN/MMAC1 is rarely associated with esophageal squamous cell carcinoma carcinogenesis.
Insights
The PTEN/MMAC1 gene, a tumor suppressor, showed normal expression in esophageal cancer cell lines and tissues. This suggests PTEN/MMAC1 is rarely involved in esophageal squamous cell carcinoma development.
Area of Science:
- Oncology
- Molecular Biology
- Genetics
Background:
- The PTEN/MMAC1 gene is a tumor suppressor gene candidate.
- Mutations in PTEN/MMAC1 are found in various tumors.
- Alternative inactivation mechanisms like promoter methylation exist.
Purpose of the Study:
- To investigate abnormalities in PTEN/MMAC1 gene expression in esophageal cancer.
- To determine the role of PTEN/MMAC1 in esophageal squamous cell carcinoma.
Main Methods:
- Reverse transcription polymerase chain reaction (RT-PCR) for mRNA detection.
- Western blot analysis for protein expression.
- Immunohistochemical staining for protein localization and expression in tissues.
Main Results:
- PTEN/MMAC1 mRNA was expressed in all esophageal cancer cell lines and normal epithelial cells.
- Western blot confirmed PTEN/MMAC1 protein expression without significant differences.
- Immunohistochemistry revealed strong cytoplasmic PTEN/MMAC1 staining in both cancer and normal esophageal tissues.
Conclusions:
- PTEN/MMAC1 gene expression is not significantly altered in esophageal squamous cell carcinoma.
- PTEN/MMAC1 is rarely associated with the carcinogenesis of esophageal squamous cell carcinoma.
