We transfected several cell lines with the recombinant cc49scFv-FasLext and L6scFv-FasLext constructs and used limiting dilution technique to obtain the clones that produced the highest cytotoxicity against the A20 tumor cells, which express Fas Ag and are sensitive to sFasL-mediated cytotoxicity [12]. This evidence concerns the gene FASLG and neoplasm.