[Amplification and rearrangement of proto-oncogene c-abl in human leukemia cells]

DNA of peripheral blood or bone marrow leukocytes from 8 normal subjects, 7 cases of acute lymphocytic leukemia (ALL), 2 of acute myelogenous leukemia (AML) and 1 of chronic myelogenous leukemia (CML), having been digested by endonuclease Eco RI or Pst I separately, was hybridized with the probes of 3' fragment (Pst I/Hind III) or 5' fragment (Hinc II/Pst I) of Abelson murine leukemia virus (A-MuLV) oncogene v-abl. The proto-oncogene c-abl, which is homologous to v-abl, was found amplified in 4 ALL, 1 CML and 1 AML. In one of these 4 ALL, c-abl was amplified even over 100 times. A new c-abl BamH I fragment with 6.7 kilobase pairs (kb) in length was observed in 2 ALL and 1 CML out of these 6 cases with amplification, but none of this fragment was found in the normal subjects or other leukemia patients. These 3 patients with the presence of 6.7 kb fragment were high risk ones and 2 of them had died, suggesting that 6.7 kb fragment be the index of poor prognosis. The amplification and rearrangement of c-abl imply the activation of proto-oncogene in leukemogenesis.