[FGFR3 overexpression is a relevant alteration in colorectal cancer]

Fibroblast growth factor receptor (FGFR) signalling plays an important role in embryogenesis as well as in tumorigenesis. In current studies FGFR has proved to be a potential molecular target in a variety of solid tumours. In colorectal cancer (CRC) data on FGFR alterations is very sparse. However, there is a huge need for targeted therapies in this tumour entity with an incidence of 140,000 individuals (USA 2018) and a 5-year relative survival rate of only 14% in metastatic disease.

This article shall provide an overview of the FGFRs and the most frequent FGF ligand alterations in primary and metastatic CRC.

In primary tumours and metastases various FGFR and FGF alterations can be observed. Primary tumours as well as metastases show FGFR alterations at the genomic (by fluorescence in situ hybridization) as well as on the ribonucleic acid (RNA) expression level (by RNA in situ hybridization). In both cohorts FGFR3 overexpression is the most frequent alteration and is associated with an unfavourable prognosis in metastases.

FGFR3 overexpression defines a subgroup of metastatic colorectal cancers with an unfavourable prognosis. Since FGFR3 alterations can present a potential therapeutic target, patients with FGFR3 overexpression should be included into clinical studies with FGFR inhibitors.