Unravelling the genomic targets of small molecules using high-throughput sequencing.

Small molecules--including various approved and novel cancer therapeutics--can operate at the genomic level by targeting the DNA and protein components of chromatin. Emerging evidence suggests that functional interactions between small molecules and the genome are non-stochastic and are influenced by a dynamic interplay between DNA sequences and chromatin states. The establishment of genome-wide maps of small-molecule targets using unbiased methodologies can help to characterize and exploit drug responses. In this Review, we discuss how high-throughput sequencing strategies, such as ChIP-seq (chromatin immunoprecipitation followed by sequencing) and Chem-seq (chemical affinity capture and massively parallel DNA sequencing), are enabling the comprehensive identification of small-molecule target sites throughout the genome, thereby providing insights into unanticipated drug effects.