Pathways of colorectal carcinogenesis

Area of Science:

• Molecular Oncology
• Gastroenterology
• Cancer Genetics

Background:

• Colorectal carcinogenesis follows an adenoma-carcinoma sequence involving genetic and epigenetic alterations.
• Genomic instability, including chromosomal instability (CIN) and microsatellite instability (MSI), is a hallmark of colorectal cancer.
• Epigenetic modifications, such as the CpG island methylator phenotype, also play a crucial role.

Purpose of the Study:

• To review the molecular and cellular changes in colorectal carcinogenesis.
• To outline the different pathways involved in colorectal cancer development.
• To categorize colorectal cancers based on their molecular and pathological characteristics.

Main Methods:

• Review of existing literature on molecular and cellular changes in colorectal cancer.
• Analysis of genetic and epigenetic alterations contributing to carcinogenesis.
• Categorization of colorectal cancers based on identified pathways and molecular features.

Main Results:

• Colorectal cancer progression involves the accumulation of genetic (CIN, MSI) and epigenetic (CpG island methylator phenotype) alterations.
• CIN is often linked to APC mutations, while MSI results from defective DNA mismatch repair.
• Familial cancer syndromes like Familial Adenomatous Polyposis Coli and Lynch Syndrome are associated with specific inherited mutations.

Conclusions:

• Colorectal cancers can be categorized into five major groups based on their distinct molecular and pathological profiles.
• Understanding the interplay of CIN, MSI, and CpG island methylator phenotype is key to classifying colorectal cancers.
• This molecular categorization provides insights into the diverse pathways of colorectal carcinogenesis.