Gene expression profiling of laterally spreading tumors

Area of Science:

• Gastroenterology
• Oncology
• Molecular Biology

Background:

• Laterally spreading tumors (LSTs) are colorectal lesions >10 mm characterized by superficial growth and potential for malignancy.
• LSTs exhibit lateral expansion along the luminal wall with a low vertical axis.
• Understanding the molecular basis of LSTs is crucial for diagnosis and treatment.

Purpose of the Study:

• To analyze the gene expression profile of LSTs.
• To identify genes with altered expression in LST-adenomas compared to pedunculated adenomas (Ip-adenomas).
• To investigate the role of specific genes, particularly BCL2L1, in LST development.

Main Methods:

• Gene expression analysis of 168 genes in 41 colorectal tumor samples using PCR array.
• Hierarchical and K-means clustering to identify up-regulated genes in LST-adenoma versus Ip-adenoma.
• Immunohistochemical staining on an additional 60 samples to confirm protein localization and expression levels.

Main Results:

• PCR array identified 129 differentially expressed genes between colorectal tumors and normal mucosa.
• Five genes (AKT1, BCL2L1, ERBB2, MTA2, TNFRSF25) were significantly up-regulated in LST-adenoma compared to Ip-adenoma (p < 0.05).
• BCL2L1 protein was significantly up-regulated in LST-adenoma (p = 0.010) and showed an anti-apoptotic role in 63.2% of samples.

Conclusions:

• LSTs possess a unique gene expression profile compared to other colorectal tumors.
• BCL2L1 is implicated in the organization and potential anti-apoptotic mechanisms within LSTs.
• Further research into BCL2L1's role could offer therapeutic targets for LSTs.