Molecular classification of colorectal carcinomas: The genotype-to-phenotype relation

Abstract

Colorectal carcinomas (CRCs) are frequently found in industrialized countries and lead to a high incidence of malignancy-related mortality. Defined by histomorphological features, CRCs and their pre-invasive lesions are quite heterogeneous. The underlying molecular mechanisms include genomic instability, genomic mutation of tumor suppressor genes or oncogenes, epigenetic changes, and the microRNA network. The molecular mechanisms are guided by repeated clonal selections. The genotype-to-phenotype relation is assumed to be the great challenge of cancer research and the development of effective targeted therapies. At present a strong genotype-to-phenotype relation is characterized only for a minority of CRCs. Consequently, the molecular characterization of CRCs is essential to interpret histological patterns and to identify prognostic groups as well as patients for targeted therapy.

Keywords: Carcinogenesis; Colorectal cancer; Molecular pathology

Core tip: Colorectal carcinomas (CRCs) are frequently found in industrialized countries. At present only a minority of CRCs are characterized by a strong genotype-to-phenotype relation. This is due to several additional factors determining phenotype expression. In conclusion, molecular characterization (genotype) is essential to interpret the histological findings (phenotype) and to identify prognostic groups as well as patients for targeted therapy.