In 1992, an exogenous ribozyme directed against the mRNA of the tumor necrosis factor α (TNFα) was delivered using lipofectin (DOTMA-DOPE mix) for cationic-liposome-mediated transfection into human promyelocytic leukemia cells (HL60) and peripheral blood mononuclear cells. The gene discussed is TNF; the disease is leukemia.