Persistence of an activating N-RAS oncogene mutation in clonogenic progenitor cells from an acute myeloid leukaemia patient in remission.

A patient with acute myeloid leukaemia (AML) with an activating N-RAS oncogene mutation was studied in a haemopoietic clonogenic progenitor cell assay. Individual colonies and clusters were analysed by polymerase chain reaction and oligonucleotide hybridization for the original mutation. The mutation was detected in a majority of leukaemic clusters, but also in almost half of the differentiated colonies. After chemotherapy the patient entered clinical remission. However, the mutation could still be detected in the bone marrow. Only differentiated colonies and no leukaemic clusters were grown from the remission bone marrow, but the original mutation was still detectable in almost half of the colonies.