Abstract: A method to prevent or treat cancer in a patient comprising: administering a first set of tumor cells; where at least some of the first tumor cells have at least one tumor antigen corresponding to antigen of the patient's tumor cells; where the tumor cells are contained in an implantable chamber; the chamber defined by a wall including a porous boundary between the patient's immune cells and the contained cells and pervious to subcellular antigenic material; where the boundary prevents contact between patient immune cells and the contained tumor cells, and where the boundary permits subcellular antigenic materials to exit the chamber; and rendering a second set of tumor cells nontumorigenic; where at least some of the second tumor cells have at least one tumor antigen corresponding to antigen of the patient's tumor cells; administering the second tumor cells to the patient without containing them in a chamber.