In prostate cancer and renal cancer, growth inhibition of tumors was observed when patients were treated with anti-β2-M polyclonal or monoclonal antibodies (32), and in myeloma and other hematological malignancies, tumor cell apopotosis was observed using monoclonal β2-M Ab and sequence-specific siRNA to β2-M (33). The gene discussed is B2M; the disease is plasma cell myeloma.