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Updated: Jul 16, 2026
28:15
Deficient Pms2, ERCC1, Ku86, CcOI in Field Defects During Progression to Colon Cancer
Published on: July 28, 2010
Laterally spreading type of colorectal adenoma exhibits a unique methylation phenotype and K-ras mutations
Sakiko Hiraoka1, Jun Kato, Masashi Tatsukawa
1Department of Gastroenterology, Okayama University Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama, Japan.
Gastroenterology
|August 8, 2006
Summary
Granular-type laterally spreading tumors (G-LST) show high prevalence of CpG island methylator phenotype (CIMP-high) and K-ras mutations, particularly in the proximal colon. This suggests a distinct carcinogenic pathway for G-LST.
Area of Science:
- Gastroenterology and Oncology
- Molecular Pathology
- Colorectal Cancer Research
Background:
- Laterally spreading tumors (LST) are superficial colorectal tumors detected by colonoscopy.
- Genetic and epigenetic profiles of LSTs, particularly granular-type LST (G-LST), are not well-characterized.
Purpose of the Study:
- To investigate the genetic and epigenetic characteristics of different types of colorectal laterally spreading tumors (LST).
- To analyze the association between macroscopic appearance, CpG island methylator phenotype (CIMP) status, and K-ras mutations in LSTs.
Main Methods:
- Analysis of 205 sporadic colorectal adenoma tissues, including protruded-type, granular-type LST (G-LST), and flat-type LST (F-LST).
- Determination of CpG island methylator phenotype (CIMP) status and examination of K-ras point mutations.
- Statistical analysis of the relationship between tumor morphology, CIMP, and K-ras mutations.
Main Results:
- G-LSTs (61%) showed a significantly higher prevalence of CIMP-high compared to protruded-type adenomas (25%).
- K-ras mutations were significantly more frequent in G-LSTs (78%) than in protruded-type adenomas (25%).
- G-LSTs in the proximal colon exhibited even higher rates of CIMP-high (85%) and K-ras mutations (92%), while F-LSTs had low prevalence of both.
Conclusions:
- The high prevalence of CIMP-high and K-ras mutations in G-LST, especially in the proximal colon, indicates a unique carcinogenic pathway.
- These findings highlight distinct molecular features of G-LST, differentiating them from other colorectal adenomas.
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