Efforts to link biological and clinical breast cancer research

Important issues that underpin efforts to link new biological data on breast cancer to clinical research are considered. While animal models have been helpful in drug development, the changes in some key markers (oestrogen receptor and Ki67) in response to hormonal therapy are very different in patients. To predict that benefit of therapy in biomarker-defined subgroups requires the parallel study of a randomized control arm. Biomarker analyses have reduced statistical power compared with whole trials. Neoadjuvant therapy is an advantageous scenario to link biological and clinical research.