Localised production of growth hormone (GH) is detectable in a variety of different human cancers, including breast cancer, and this is associated with an increased risk of metastasis and reduced survival for breast cancer patients. In contrast, humans and animals born with a deficiency in the cell surface receptor for GH have a dramatically reduced, almost absent, risk of developing cancer. Consequently, inhibiting the action of GH is a promising strategy for treating breast cancer. Results obtained in preliminary studies have been promising, but studies into the efficacy of this approach are limited by the availability of inhibitors of GH signalling. We will discover and develop small molecule inhibitors of the GH receptor and explore their use to treat breast cancer. We will use a specialised high-throughput assay to identify molecules that bind to the GH receptor and test these ""hits"" in biological assays to confirm efficacy and therapeutic potential.