RAS mutations are found in about 25% of acute myeloid leukemia (AML) c
ases. The importance of these changes is unknown, If RAS mutations con
fer growth advantage to leukemia subclones in which they emerge, subst
antially more nonconservative than conservative mutations should be fo
und. The incidence of conservative mutations was not reported previous
ly. We sequenced N-RAS and K-RAS codons 12 and 13 and N-RAS codon 61 i
n 20 subjects with newly diagnosed AML. Four nonconservative N-RAS mut
ations and 4 conservative K-RAS mutations were found. There were no di
fferences between subjects with AML and nonconservative RAS mutations
and those with conservative or without RAS mutations, Additional. stud
ies are needed to examine the incidence of conservative RAS mutations
in subjects with AML.