Multiple truncated transcripts of TSG101 in gastrointestinal cancers

Area of Science:

• Molecular Biology
• Oncology
• Genetics

Background:

• The tumor suppressor gene TSG101 is implicated in breast cancer due to intragenic deletions.
• Understanding TSG101 alterations in other cancers is crucial for its role as a tumor suppressor.

Purpose of the Study:

• To investigate the occurrence and splicing patterns of TSG101 truncated transcripts in gastrointestinal cancers.
• To analyze TSG101 gene expression in gastric, colorectal, and esophageal tumors and matched normal tissues.

Main Methods:

• Nested reverse transcriptase-polymerase chain reaction (RT-PCR) and direct sequencing were employed.
• Analysis focused on exons 1-6 of the TSG101 gene in 32 gastric, 30 colorectal, and 16 esophageal cancer samples.
• Paired tumor and normal tissues were utilized to identify cancer-specific alterations.

Main Results:

• Truncated TSG101 transcripts were detected in both tumor and normal tissues across all studied gastrointestinal cancers.
• Prevalence rates for truncated transcripts varied: stomach (15.6% tumor, 12.5% normal), colon (13.3% tumor, 3.3% normal), and esophagus (25% tumor, 25% normal).
• Specific splicing patterns, including homology at deletion junctions and canonical splice donor/acceptor sites (GT-AG), were identified as common.

Conclusions:

• Truncated TSG101 transcripts are not uncommon in gastrointestinal cancers.
• These truncations exhibit specific, recurring splicing patterns.
• The presence of truncated transcripts in normal tissues suggests potential germline variations or widespread alternative splicing of TSG101.