Lysates were clarified from sonicated nuclei and ETV6-HA/DNA complexes were isolated with Anti-HA magnetic beads. Protein/DNA complexes were eluted from the beads by competition with HA peptides prior to reverse-crosslinking and standard purification using phenol/chloroform/isoamyl alcohol The purified ChIP DNA was processed through TruSeq ChIP Sample Preparation Kit (Illumina) according to the manufacturer protocol