FLCN and colorectal carcinoma: The authors propose that FLCN might be a driver gene for CRC in the African American population, but further studies are necessary to confirm this.23 As far as we know, only one colorectal tumour from a BHD patient has been assessed for a second hit in FLCN. By sequencing tumour DNA and normal tissue, loss of heterozygosity at the locus of the germline FLCN mutation was shown.24 Since only one tumour was tested, this observation does not prove a causal role of loss of FLCN in the development of this tumour.