NRAS MUTATIONS ARE RARE IN ACUTE MYELOID LEUKEMIAS WITH T(8-21) OR INV(16)

Using PCR and direct sequence methodology, 19 haematologic malignancie s with trisomy 8, 18 with t(8;21)(q22;q22) and 8 with inv(16)(p13q22) were screened for NRAS mutations. Of the 45 samples analyzed, 4 (9%) h ad a mutation; both wild-type and mutated alleles were observed in the se 4 cases. Three of the mutations (involving codons 12 and 13) were f ound in the trisomy 8 group and 1 (codon 61) among the inv(16) samples . No specific clinical similarities were found in the 3 patients with + 8 and NRAS mutation. By analyzing two sequential samples from the pa tient with inv(16) and NRAS mutation, it was shown that the mutation h ad occurred after the inversion. Since no NRAS mutations were detected among the t(8;21) samples and only 1 was found in the inv(16) group, we conclude that acute myeloid leukaemias with t(8;21) or inv(16) gene rally arise and progress without the involvement of NRAS mutations.