Once a cancer grows beyond a certain point, the immune system has a hard time fighting it. One reason is that cancer cells look a lot to the immune system like normal cells. Another reason is that tumors may give off signals that manipulate the immune system into leaving them alone. Provenge bypasses these problems. The treatment first removes a quantity of dendritic cells from a patient's blood. Dendritic cells show pieces of tumor to immune cells, priming them to attack cells that carry those pieces. The patient's doctor ships the cells to Provenge's manufacturer, Dendreon, which then exposes them to Provenge. Provenge is a molecule made inside genetically engineered insect cells. Once these cells have been exposed to Provenge, they're shipped back to the doctor who infuses them back into the patient. This is done three times in one month. The first infusion primes the immune system. The second and third doses spur an anticancer immune response.