Cytoplasmic nucleophosmin in acute myelogenous leukemia with a normal karyotype

Brunangelo Falini, Cristina Mecucci, Enrico Tiacci, Myriam Alcalay, Roberto Rosati, Laura Pasqualucci, Roberta La Starza, Daniela Diverio, Emanuela Colombo, Antonella Santucci, Barbara Bigerna, Roberta Pacini, Alessandra Pucciarini, Arcangelo Liso, Marco Vignetti, Paola Fazi, Natalia Meani, Valentina Pettirossi, Giuseppe Saglio, Franco MandelliFrancesco Lo-Coco, Pier Giuseppe Pelicci, Massimo F. Martelli

Research output: Contribution to journalArticlepeer-review


BACKGROUND: Nucleophosmin (NPM), a nucleocytoplasmic shuttling protein with prominent nucleolar localization, regulates the ARF-p53 tumor-suppressor pathway. Translocations involving the NPM gene cause cytoplasmic dislocation of the NPM protein. METHODS: We used immunohistochemical methods to study the subcellular localization of NPM in bone marrow-biopsy specimens from 591 patients with primary acute myelogenous leukemia (AML). We then correlated the presence of cytoplasmic NPM with clinical and biologic features of the disease. RESULTS: Cytoplasmic NPM was detected in 208 (35.2 percent) of the 591 specimens from patients with primary AML but not in 135 secondary AML specimens or in 980 hematopoietic or extrahematopoietic neoplasms other than AML. It was associated with a wide spectrum of morphologic subtypes of the disease, a normal karyotype, and responsiveness to induction chemotherapy, but not with recurrent genetic abnormalities. There was a high frequency of FLT3 internal tandem duplications and absence of CD34 and CD133 in AML specimens with a normal karyotype and cytoplasmic dislocation of NPM, but not in those in which the protein was restricted to the nucleus. AML specimens with cytoplasmic NPM carried mutations of the NPM gene that were predicted to alter the protein at its C-terminal; this mutant gene caused cytoplasmic localization of NPM in transfected cells. CONCLUSIONS: Cytoplasmic NPM is a characteristic feature of a large subgroup of patients with AML who have a normal karyotype, NPM gene mutations, and responsiveness to induction chemotherapy.

Original languageEnglish
Pages (from-to)254-266
Number of pages13
JournalNew England Journal of Medicine
Issue number3
Publication statusPublished - Jan 20 2005

ASJC Scopus subject areas

  • Medicine(all)


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