Previous studies have shown that the bcl-2protooncogene encodes a mitochondrial protein thatpromotes cell survival by blocking programmed celldeath. High levels of bcl-2 expression were found inmurine myeloid leukemic cell lines resistant to apoptosisinduced by variety of agents. In addition artificialelevation of bcl-2 expression in a human pre-B leukemiccell line resulted in enhanced resistance to chemo-therapcutic drugs. We reported here on the effect ofbcl-2 antisense phosphorothiate oligodeoxynucleotides Previous studies have shown that the bcl-2protooncogene encodes a mitochondrial protein thatpromotes cell survival by blocking programmed celldeath. High levels of bcl-2 expression were found inmurine myeloid leukemic cell lines resistant to apoptosisinduced by variety of agents. In addition artificialelevation of bcl-2 Expression in a human pre-B leukemiccell line resulted in enhanced resistance to chemo-therapcutic drugs. We reported here on the effect ofbcl-2 antisense phosphorothiate oligodeoxynucleotides