A new study outlines a computational method, termed DAISY, that statistically infers synthetic lethal interactions from cancer genomic data derived from cell lines and clinical samples. Jerby-Arnon et al. then used this method to construct genome-wide synthetic lethal interaction networks and exploited this network to predict the response of various cancer cell lines to anticancer drugs. The authors suggest that their approach can be used to triage current approaches based on the genetic makeup of a patient's tumour, to repurpose currently available drugs, to identify novel drug targets, and to predict prognosis.