The use of olaparib is slightly distinct in breast, prostate and pancreatic cancers, but still focuses on patients who have HR defective cancers, defined either by the presence of deleterious BRCA1 or BRCA2 mutations or in the case of prostate cancers, by the presence of deleterious mutations in any one of a panel of genes that control HR [42]. The gene discussed is BRCA1; the disease is cancer.