Using SW480 colon cancer cells, we performed chromatin immunoprecipitation followed by deep sequencing (ChIP-seq) for RNAPII and TOP1 and measured TOP1 catalytic activity using TOP1 sequencing (TOP1-seq; Fig. 5B), a method for identifying only catalytically engaged TOP1 (TOP1cc) (22). The gene discussed is TOP1; the disease is malignant colon neoplasm.