Immunohistochemistry predicts nucleophosmin (NPM) mutations in acute myeloid leukemia
Immunohistochemistry predicts nucleophosmin (NPM) mutations in acute myeloid leukemia
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DOI：
10.1182/blood-2006-03-007013
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发表时间：
2006-09-15
期刊：
影响因子：
20.3
通讯作者：
Mecucci, Cristina
中科院分区：
文献类型：
--
作者：
Falini, Brunangelo;Martelli, Maria Paola;Mecucci, Cristina
在核型正常的成人急性髓系白血病(AML)中，核磷蛋白(NPM)外显子-12突变的发生率为50%~60%，是预后良好的预测指标。我们评估了450例GIMEMA(Gruppo Italiano Malattie Ematologiche Maligne Dell‘Adulto)/AML12 EORTC(欧洲癌症研究和治疗组织)试验的AML成人患者的骨髓或外周血样本，以(1)寻找新的外显子-12 NPM突变；(2)确定石蜡包埋活检组织上的NPM免疫染色是否预测NPM突变；以及(3)调查原代AML细胞核浆NPM运输的变化。共鉴定出14个NPM突变，其中包括8个新变异体。200例胞浆NPM表达的AML(NPMc(+)AML)均携带NPM突变。250例核限制性NPM(NPMc(-)AML)均未发生突变。在C末端，NPM白血病突变体仅携带色氨酸290或同时携带色氨酸288和290的突变，以及一个新的核输出信号(NES)基序，这似乎是其核输出的基础。在原代NPMc(+)AML细胞中，特异性CRM1/exportin-1抑制剂Leptomycin-B将NPM突变体从胞浆重新定位到胞核，说明胞核输出是NES依赖性的。NPM突变体结合并招募野生型NPM进入白血病细胞胞浆。由于白血病NPM突变体的C末端改变相似，免疫组织化学检测所有外显子-12 NPM突变，对于核型正常的AML患者的诊断和预后评估是一种有价值的、廉价的工具。
Nucleophosmin (NPM) exon-12 mutations occur in 50% to 60% of adult acute myeloid leukemia (AML) with normal karyotype and are predictors of favorable prognosis. We evaluated bone marrow or peripheral blood samples from 450 adult patients with AML of the GIMEMA (Gruppo Italiano Malattie Ematologiche Maligne dell'Adulto)/AML12 EORTC (European Organization for Research and Treatment of Cancer) trial to (1) search for new exon-12 NPM mutations; (2) determine whether NPM immunostaining on paraffin-embedded biopsies predicts NPM mutations; and (3) investigate altered nucleocytoplasmic NPM traffic in primary AML cells. Fourteen NPM mutations, including 8 new variants, were identified. All 200 AML cases expressing cytoplasmic NPM (NPMc(+) AML) carried NPM mutations. None of the 250 cases with nucleus-restricted NPM (NPMc(-) AML) was mutated. At the C-terminus, NPM leukemic mutants carried mutations of only tryptophan 290 or of both tryptophans 288 and 290 and a new nuclear export signal (NES) motif, which appear to underlie their nuclear export. The specific Crm1/exportin-1 inhibitor leptomycin-B relocated NPM mutants from cytoplasm to nucleus of primary NPMc(+) AML cells, demonstrating that nuclear export is NES dependent. NPM mutants bound and recruited wildtype NPM into leukemic cell cytoplasm. Because alterations at C-terminus of leukemic NPM mutants are similar, immunohistochemistry detects all exon-12 NPM mutations and is a valuable, inexpensive tool in the diagnostic-prognostic work-up of patients with AML with normal karyotype.