COEXPRESSION OF C-ABL AND C-MYB ONCOGENES IN PHILADELPHIA CHROMOSOME-NEGATIVE, BCR-NEGATIVE CHRONIC MYELOID-LEUKEMIA

Three cases of Philadelphia (Ph) chromosome-negative, bcr-negative chr onic myeloid leukaemia (CML) have been investigated for oncogene expre ssion by Northern blot and cytoplasmic RNA dot blot hybridization. Con siderably high levels of expression of c-abl and c-myb were observed i n all cases. In the Ph-negative cells the normal 6.0 and 7.0 kb c-abl and 3.8 kb c-myb transcripts were found. No amplification of c-abl or c-myb oncogenes was detected in the DNAs of Ph-negative CML cells. Dat a suggest that co-operation between the overexpressed c-abl and c-myb oncogenes is causally related to Ph-negative, bcr-negative CML.