Detection of NPM exon 12 mutations and patient outcome. PCR fragment analysis of NPM exon 12 amplification showed (A) one peak in patients with NPMwt and (B) an additional peak at 301 bp in mutated patients, corresponding to a 4 bp insertion. (C) Overall survival, (D) relapse-free survival, and (E) event-free survival are shown for NPMwt and NPMm patients.