The present invention is drawn to immunotherapeutic methods to treat tumors/cancers that produce progastrin ectopically or are dependent on progastrin for their growth. Disclosed herein are immunogenic compositions comprising agents that target progastrin, agents that target the progastrin receptor, annexin II, or both. Such a composition may be administered in combination with chemotherapy or to an individual who had been previously subjected to chemotherapy or radiation therapy. The cancers that may be treated using such a composition may include but are not limited to colon cancer, breast cancer, lung cancer or pancreatic cancer.