Nucleophosmin (NPM1) gel analysis/hybridization. (A) Hybridization to wild-type NPM1 probe confirms the presence of wild-type NPM1 in 7 patient specimens and 3 cell lines (specimens 8 to 10). All 165 AML samples contained wild-type NPM1. (B) Patient specimen (1, 3-5, 7) hybridized to NPM1 variant A probe consistent with an NPM1 variant type A mutation (see Supplement).⁴⁴