RESUMO
OBJECTIVES: To establish the frequency of JAK2, MPL and CALR mutations in Argentinean patients with BCR-ABL1-negative myeloproliferative neoplasms (MPN) and to compare their clinical and haematological features. METHODS: Mutations of JAK2V617F, JAK2 exon 12, MPL W515L/K and CALR were analysed in 439 Argentinean patients with BCR-ABL1-negative MPN, including 176 polycythemia vera (PV), 214 essential thrombocythemia (ET) and 49 primary myelofibrosis (PMF). RESULTS: In 94.9% of PV, 85.5% ET and 85.2% PMF, we found mutations in JAK2, MPL or CALR. 74.9% carried JAK2V617F, 12.3% CALR mutations, 2.1% MPL mutations and 10.7% were triple negative. In ET, nine types of CALR mutations were identified, four of which were novel. PMF patients were limited to types 1 and 2, type 2 being more frequent. DISCUSSION: In ET, patients with CALR mutation were younger and had higher platelet counts than those with JAK2V617F and triple negative. In addition, JAK2V617F patients had high leucocyte and haemoglobin values compared with CALR-mutated and triple-negative patients. In PMF, patients with mutant CALR were associated with higher platelet counts. CONCLUSION: Our study underscores the importance of JAK2, MPL and CALR genotyping for accurate diagnosis of patients with BCR-ABL1-negative MPN.
Assuntos
Calreticulina/genética , Proteínas de Fusão bcr-abl/genética , Janus Quinase 2/genética , Mutação , Transtornos Mieloproliferativos/genética , Receptores de Trombopoetina/genética , Idoso , Argentina , Calreticulina/metabolismo , Feminino , Proteínas de Fusão bcr-abl/metabolismo , Humanos , Janus Quinase 2/metabolismo , Masculino , Pessoa de Meia-Idade , Transtornos Mieloproliferativos/sangue , Transtornos Mieloproliferativos/metabolismo , Receptores de Trombopoetina/metabolismoRESUMO
OBJECTIVES: Mutations in the C-terminal region of the nucleophosmin (NPM1) gene occur in approximately 60% of acute myeloid leukemia (AML) cases with normal karyotype and represent the most common genetic lesion presently known in this disease. Because of their frequency and favorable impact on prognostic outcome, screening for this aberration is currently recommended in routine diagnostic characterization of AML. Several techniques enabling to detect NPM1 mutation have been reported, but all require sophisticated equipment, which represent an obstacle particularly in countries with limited resources. METHODS: We designed an RT-PCR strategy to amplify NPM1 exon 12 followed by electrophoresis and fragment visualization on polyacrylamide gels to discriminate a 4-5 bp size difference resulting from mutations in this gene. A hemi-nested method was designed to increase sensitivity for the study of minimal residual disease (MRD). RESULTS: The assay enabled specific detection of NPM1 mutations in 12/36 patients. A 10(-2) sensitivity level was obtained using one amplification round, while the hemi-nested PCR approach yielded a 10(-5) sensitivity level, therefore proving useful to assess MRD in patients carrying the mutation. The results were independently validated in 24 AML cases by sequencing analysis. CONCLUSIONS: This simple and low-cost assay may integrate diagnostic work-up of AML and could be used for assessment of response to therapy in patients with NPM1 mutations.