Despite decades of research, current cancer therapies extend survival but often do not actually cure the disease. Immune cell based therapy is described here that can eliminate tumor cells without the toxicity associated with chemotherapy or allogeneic bone marrow transplant (BMT). Allogeneic BMT has beneficial graft vs. tumor (GVT) effects but accompanied by the undesirable graft vs. host disease (GVHD). The mechanism described here relates to generating the Mirror Effect™ that elicits a host vs. tumor (HVT) effect along with a non-toxic host vs. graft (HVG) response. The HVT effect generated by inducing the Mirror Effect™ in a host is effective in cancer therapy, as well as other diseases. The patent strategy, employed for successful patent prosecution related to the elucidation of the Mirror Effect™, is also discussed.