TET1 and gastric cancer: Next, we performed epigenetic editing by using CRISPR-dCas9 based technologies, such as the casilio system [14] for targeted methylation with a DNMT3A-3 L fusion protein and the dCas9-SunTag scaffold with scFv–TET1 catalytic domain fusions [15] for targeted demethylation to the intended genomic sites in the AGS human gastric cancer cell line (Additional file 4: Table S3).