RAS mutations in elderly AML.

(A) SSCP of PCR products fromNRAS exon 1. Banding patterns from the following samples are demonstrated: normal bone marrow (NL, left lane), THP1 (a positive control with known mutation in exon 1 of RAS), and elderly AML samples 34 to 43. Arrows point to shifted bands in THP1, 39, and 43. Direct nucleotide sequencing confirmed mutations in NRASexon 1 for THP1, 39, and 43. (B) Chart revealing the frequency of specific amino acid substitutions (vertical axis) in NRASand KRAS as separated by individual codons (horizontal axis). Alanine (A), arginine (R), aspartic acid (D), cysteine (C), valine (V), and all other amino acids (O).