 Drugs known as HER2-targeted therapies are often used to treat HER2-positive cancers. HER2-targeted therapies work by blocking the HER2 protein from telling the cell to grow and divide. Once the protein stops working, the cancer cells can no longer make copies of themselves. Once a cancer cell becomes unable to make copies of itself, the tumor will start to shrink. However, some tumors are able to find other ways to make copies of themselves, even when the HER2 protein is blocked. When this happens, the cancer will start to grow again. Researchers believe that adding a drug called simvastatin to an anti-HER2 therapy regimen may cause the cancer to start responding again to your HER2-medications. 