Garvan Institute of Medical Research, National Health and Medical Research Council of Australia, and University of New South Wales. Christopher Ormandy is Head of the Development Group of the Cancer Research Program at the Garvan Institute of Medical Research. He is a Research Fellow of the National Health and Medical Research Council of Australia and an Associate Professor in the St Vincent’s Hospital Clinical School, University of New South Wales. The Development Group works to discover the genetic program that underlies the normal developmental processes that build a mammary gland and control its function. These genes are targets for mutation or dysregulation during carcinogenesis, perturbing the normal process they control to influence the phenotype of the resulting cancer. These genes provide excellent candidates for development as new therapeutic targets or prognostic markers. The Development Group has recently discovered that the transcription factor Elf5 controls progenitor cell fate decisions during mammary development, and that Elf5 greatly influences aspects of breast cancer phenotype such as sensitivity to estrogens, molecular subtype, epithelial to mesenchymal transition and metastatic activity.