An international consortium of 7 research teams, including the CIT team, just published in Nature Medicine [1] a consensus classification of colorectal cancers (CRC) based on gene expression data.
Based on the analysis of more than 4,000 tumor samples, this work lead to a consensus on the existence of 4 molecular subtypes of colorectal cancers, thoroughly characterized at the molecular and clinical level :
- The ‘MSI immune’ type (14% of cases) : hypermutated tumors, with a majority bearing microsatellite instability (MSI) and a prominent immune infiltration,
- The ‘Canonical‘ type (37% of cases) : tumors with chromosomal instability and mutations in the APC and TP53 genes, illustrating the canonical carcinogenesis described by Fearon and Vogelstein in 1990,
- The ‘Metabolic‘ type (13% of cases) : chiefly mutated in the KRAS oncogene and overexpress metabolic pathways,
- The ‘Mesenchymal‘ type (23% of cases), associated to a bad prognosis : highly infiltrated tumors that overexpress genes of the Epithelial-Mesenchymal transition.
It is the first international collaboration that successfully lead to the molecular classification of a cancer. The classification into 4 molecular subgroups can hereon be used as a standard by the scientific community, in particular for the identification of targeted therapy and for the stratification of clinical trials.
