Colorectal Cancer

Colorectal Cancer (CRC), more frequently detected in western countries, is caused by mutations in target oncogenes, tumor suppressor genes and genes related to DNA repair mechanisms. CRC is classified into 3 types depending on the origin of the mutation: Sporadic (70%), inherited (5%) and familial (25%)[1].

Sporadic cancer: These cancers are derived from point mutations and account for 70% of CRC. The occurrence of mutations follow a specific sequence which is followed by a morphological sequence.

colorectal-cancer img

Adenomatous polyposis coli (APC), a tumor suppressor gene, is the first gene to be mutated leading to the formation of a non-malignant adenomas called polyps. 15% of all adenomas progress to full blown carcinomas over 10 years.

Key genes mutated in Sporadic CRC

APC KRAS TP53 DCC SMAD4 BRAF


Inherited cancer: In the inherited form of CRC, one of the mutation is inherited. The 2nd mutation triggers the apparition of the tumor cell and finally resulting in carcinoma. Inherited CRC is classified into two groups: polyposis and non-polyposis forms. Polyposis mainly involved familial adenomatous polyposis (FAP) which is characterized by the formation of multiple polyps in the colon. Hereditary non-polyposis colorectal cancer (HNPCC) is related to mutation in DNA repair mechanisms. Lynch syndrome is the main cause of hereditary non-polyposis colorectal cancer.

Key genes mutation in Lynch syndrome

MLH1 MSH2 MSH6 PMS1

Tissue samples for Colorectal Cancer

Frozen Sections Tissue Protein Lysates Total RNA FFPE Sections Tissue Genomic DNA

References:

  1. Mármol I, Sánchez-de-Diego C, Pradilla Dieste A, Cerrada E, Rodriguez Yoldi MJ. Colorectal Carcinoma: A General Overview and Future Perspectives in Colorectal Cancer. Int J Mol Sci. 2017 Jan 19;18(1):197.