VAL-3 cells were treated with 1% paraformaldehyde for chromatin cross-linking before cell lysis and sonication to generate DNA fragments. Fragmented chromatin mixed with Dynabeads protein G was incubated with either FOXM1 antibody or rabbit IgG at 4°C overnight. Successive rounds of magnetic clearance were performed, followed by crosslink reversal with NaCl incubation and protein digestion with proteinase K. DNA was purified using the Wizard® PCR clean-up system (Promega) Libraries were prepared according to Illumina's instructions. Briefly, DNA-end was repaired to overhang a 3'-dA, then adapters were ligated to the end DNA fragments. DNA fragments with proper size (usually 100-300bp, including adaptor sequence) were selected after PCR amplification, followed by library construction.