Circulating insulin-like growth factor II and colorectal adenomas

Area of Science:

• Endocrinology
• Gastroenterology
• Oncology

Background:

• Insulin-like growth factor I (IGF-I) and IGF-binding protein-3 (IGFBP-3) roles in colorectal cancer are debated.
• Insulin-like growth factor II (IGF-II) and IGFBP-2 are upregulated in colorectal carcinomas.

Purpose of the Study:

• To investigate the association between serum IGF-I, IGF-II, IGFBP-2, and IGFBP-3 levels and the presence of colorectal adenomas.
• To evaluate changes in these markers after adenoma removal.

Main Methods:

• Cross-sectional study of 345 healthy volunteers (aged 55-64) undergoing flexible sigmoidoscopy.
• Serum levels of IGF-I, IGF-II, IGFBP-2, and IGFBP-3 were measured.
• Logistic regression analysis adjusted for confounding factors.
• Immunohistochemical analysis of IGF-II expression in adenomas and normal colonic tissue.

Main Results:

• Elevated mean serum IGF-II was observed in individuals with adenomas compared to controls (P < 0.0001).
• Significant positive associations were found between adenoma occurrence and serum IGF-II (P < 0.0001) and IGFBP-2 (P < 0.0001).
• Serum IGF-I and IGFBP-3 showed no association with adenoma presence.
• IGF-II was expressed in 83% of adenomas but not in normal colonic tissue.
• Adenoma removal led to a significant decrease in serum IGF-II and IGFBP-2 levels (P < 0.001).

Conclusions:

• Serum IGF-II may serve as a potential tumor marker for colorectal adenomas.
• Serum IGFBP-2 is also associated with colorectal adenomas.
• Further validation in larger populations, including those undergoing colonoscopy, is warranted.