Rego de Paula Junior Milton, Nonino Alexandre, Minuncio Nascimento Juliana, Bonadio Raphael S, Pic-Taylor Aline, de Oliveira Silviene F, Wellerson Pereira Rinaldo, do Couto Mascarenhas Cintia, Forte Mazzeu Juliana
Programa de Pós-graduação em Ciências Médicas, Universidade de Brasília, Brasília, Brazil.
Cytogenet Genome Res. 2018;154(2):62-70. doi: 10.1159/000487627. Epub 2018 Mar 22.
Myelofibrosis is the rarest and most severe type of Philadelphia-negative classical myeloproliferative neoplasms. Although mutually exclusive driver mutations in JAK2, MPL, or CALR that activate JAK-STAT pathway have been related to the pathogenesis of the disease, chromosome abnormalities have also been associated with the phenotype and prognosis of the disease. Here, we report the use of a chromosomal microarray platform consisting of both oligo and SNP probes to improve the detection of chromosome abnormalities in patients with myelofibrosis. Sixteen patients with myelofibrosis were tested, and the results were compared to karyotype analysis. Driver mutations in JAK2, MPL, or CALR were investigated by PCR and MLPA. Conventional cytogenetics revealed chromosome abnormalities in 3 out of 16 cases (18.7%), while chromosomal microarray analysis detected copy-number variations (CNV) or copy-neutral loss of heterozygosity (CN-LOH) alterations in 11 out of 16 (68.7%) patients. These included 43 CN-LOH, 14 deletions, 1 trisomy, and 1 duplication. Ten patients showed multiple chromosomal abnormalities, varying from 2 to 13 CNVs or CN-LOHs. Mutational status for JAK2, CALR, and MPL by MLPA revealed a total of 3/16 (18.7%) patients positive for the JAK2 V617F mutation, 9 with CALR deletion or insertion and 1 positive for MPL mutation. Considering that most of the CNVs identified were smaller than the karyotype resolution and the high frequency of CN-LOHs in our study, we propose that chromosomal microarray platforms that combine oligos and SNP should be used as a first-tier genetic test in patients with myelofibrosis.
骨髓纤维化是费城染色体阴性经典骨髓增殖性肿瘤中最罕见、最严重的类型。尽管激活JAK-STAT通路的JAK2、MPL或CALR中相互排斥的驱动突变与该疾病的发病机制有关，但染色体异常也与该疾病的表型和预后相关。在此，我们报告使用一个由寡核苷酸和单核苷酸多态性（SNP）探针组成的染色体微阵列平台，以提高对骨髓纤维化患者染色体异常的检测。对16例骨髓纤维化患者进行了检测，并将结果与核型分析进行比较。通过聚合酶链反应（PCR）和多重连接探针扩增（MLPA）研究JAK2、MPL或CALR中的驱动突变。传统细胞遗传学显示16例中有3例（18.7%）存在染色体异常，而染色体微阵列分析在16例患者中的11例（68.7%）检测到拷贝数变异（CNV）或拷贝中性杂合性缺失（CN-LOH）改变。这些改变包括43个CN-LOH、14个缺失、1个三体和1个重复。10例患者显示多个染色体异常，从2个到13个CNV或CN-LOH不等。通过MLPA检测JAK2、CALR和MPL的突变状态，结果显示共有3/16（18.7%）患者JAK2 V617F突变呈阳性，9例CALR缺失或插入，1例MPL突变呈阳性。鉴于我们研究中鉴定出 的大多数CNV小于核型分辨率以及CN-LOH的高频率，我们建议将结合寡核苷酸和SNP的染色体微阵列平台用作骨髓纤维化患者的一线基因检测。
