Absence of nucleophosmin 1 (NPM1) gene mutations in common solid cancers.

Nucleophosmin is a nucleolar phosphoprotein that shuttles between nucleus and cytoplasm. Recent reports demonstrated that exon 12 of the nucleophosmin 1 (NPM1) gene was frequently mutated in acute myelogenous leukemias (AMLs). To see whether the NPM1 mutation occurs in other malignancies, we analyzed exon 12 of NPM1 for the detection of somatic mutations in 467 carcinomas, including 142 lung, 47 hepatocellular, 93 breast, 103 colorectal and 82 gastric carcinomas, by single-strand conformation polymorphism assay. We also analyzed the NPM1 mutation in 142 acute leukemias, including 105 AMLs. We detected 15 NPM1 mutations in the AMLs (14.3%), but there was no NPM1 mutation in the other malignancies analyzed. Our data indicate that NPM1 exon 12 is mutated in AMLs, but not in other common human cancers, and suggest that the NPM1 mutation may not play a role in the tumorigenesis of common solid cancers.