Ten million vehicle or TOP2 poison-treated K562 cells were lysed with RIPA buffer and the lysates sonicated to fragment the DNA to 250-750bp. TOP2A was immunocaptured with anti-TOP2A IgG and Protein G magnetic beads, the bead-bound fraction separated, and immunoprecipitation repeated twice on non-bound fractions. The bead-bound fractions were combined and treated with CIP (NEB) to detach the TOP2A-bound DNA from cleavage complexes. The released DNA and input DNA from sonicated lysates were purified and used directly for library synthesis with an IlluminaTruSeq ChIP library kitor pre-amplified with a SEQXE kit (Sigma) before library preparation. Sequencing was performed on an Illumina HiSeq2500 (SE50 protocol)