A study that links tumor genomes with anticancer drugs to support genetic approaches to treatment has produced the world’s largest public repository of its kind. The Genomics of Drug Sensitivity in Cancer project has announced that, with its latest data release, it has characterized 1,000 human cancer cell lines; screened them with 453 drugs, both approved and experimental; and identified close to half a million genome–drug associations. The data in this carefully curated dataset, which are free to access on the open source website, have proven to be a valuable resource for the research community and a formidable resource towards improving patient response during cancer treatment by enabling personalized clinical decisions. The genomic variants could also prove to be biomarkers for response to drugs. Funding for the project is from the UK-based Wellcome Trust, and the work was done by researchers at the Wellcome Sanger Institute in Cambridge and integrated with Boston’s Broad Institute’s Cancer Dependency Map project. The website has 350 users logging on each day, and project leaders say the dataset has supported more than 70 research studies, including the discovery of PARP inhibitors in childhood bone cancer.