We thank Dr Valerie Corrigall (University College London) for provision of recombinant GRP78, Yvonne Stephenson and Sian Leech (Core Histology Service and Department of Human Nutrition, University of Sheffield) for technical advice and Dr Christopher Connolly for staining the DCIS sections (Chesterfield Royal Hospital). Here, HSPA5 is linked to ductal breast carcinoma in situ.