Participants are randomly assigned to receive injections of one of two different vaccines (LMP-2:340-349 or LMP-2:419-427) to determine which peptide may offer the best immunity. Each treatment course consists of weekly immunizations for 8 consecutive weeks. The injections are given under the skin of the thigh. After every other treatment course (about every 3 months), patients undergo a series of x-rays and scans to look for tumor. The immunizations are given at the NIH Clinical Center. Patients are monitored for 1 hour after each injection and have blood tests and a physical examination to look for treatment side effects. Immunizations may continue for up to 12 months as long as the cancer does not return.