TET1 and colorectal carcinoma: To further explore the functional role of the observed promoter hypermethylation in CRC samples, we set up an epigenetic-editing strategy based on the expression of chimeric proteins in which the catalytic domain of the methylcytosine dioxygenase TET1 is fused to a dead Cas9 nuclease, thus permitting the specific in-vivo targeting of this complex at a certain genomic locus in the presence of their corresponding guide RNAs.