TET1 and colorectal carcinoma: To determine the functional consequences exerted by these inferred epigenetic aberrations, we modulated the DNA methylation status of 56 promoters displaying strong epigenetic repression in CRC using a customized arrayed gRNA library and the CRISPR-dCas9 epigenome and transcriptional editing toolbox (dCas9-TET1, dCas9-TET-IM, dCas9-VP64), and the potential functional consequences of this epigenetic reactivation were addressed by means of a high-content cell viability screen of DLD1 and HCT116 cells.