The restricted success of the different treatments against breast cancer combined with new evidence suggesting that this type of cancer is much more complex than we previously thought, show that additional research to identify better therapeutic targets is required. We identified, characterized, and cloned a novel gene, RHAMM/HMMR, which is required for the invasion of an aggressive type of breast cancer cell and which is also a novel breast cancer susceptibility gene. We have identified a potential mechanism by which this gene transforms cells into a cancerous state. In this research project, we will further investigate this mechanism and determine if it is the cause of the oncogenic effect of RHAMM in breast cancer. Since RHAMM is not expressed by most normal tissues but only during repair of severe wounds and in cancer, we expect RHAMM-based therapeutics will be less toxic than current therapies.