Onkológia 5/2014

Molecular biology of colorectal cancer from the perspective of the pathologist

Colorectal cancer was considered as a homogeneous entity for a long time. However, on the basis of morphology we recognize several subtypes of carcinomas which differ also at molecular genetic level. Findings from histomorphology and molcular genetic both led to discover two cardinal pathways of carcinogenesis. Approximately 60 – 80% of colorectal cancers arising via the conventional supressor pathway with conventional adenoma give rise to microsatelite stable (MSS) or chromosomal instable (CIN) carcinoma. Most of the remainder arising via the serrated pathway, with serrated adenomas give rise to CpG island methylated carcinomas that may be microsatelite instable (MSI-H). It´s quite clear toady that there is overlap between pathways. Effort to introduce the molecular classification of colorectal cancer is a pressing issue and has been extensively studied however until now without consensus. This interest is in large part driven by the need to identify key genes that are potentional targets for targeted therapies for colorectal cancer patients.

Keywords: precursor lesions, colorectal carcinoma,carcinogenesis,conventional pathway, serrated pathway.