TET1 and neoplasm: We then explored the overlap between sites with SNVs/indels in Tet2−/− tumours and three different genomic loci: (1) sites with no change in 5hmC/5mC peaks, presumably representing the sites with 5mC oxidation catalysed by TET1/3, but not TET2; (2) sites with 5hmC peak loss or 5mC peak gain, representing the 5mC sites that are converted to 5hmC by TET2; and (3) sites with 5hmC peak gain, likely representing the 5hmC sites that are further oxidized to 5fC/5caC by TET2 (Fig. 4c).