Laboratoire de Biologie Cellulaire, AP-HP, Hopital Saint-Louis, Paris, France.
Université de Paris, U1131 INSERM, IRSL, Paris, France.
Int J Lab Hematol. 2020 Dec;42(6):827-832. doi: 10.1111/ijlh.13282. Epub 2020 Jul 2.
The pathogenesis of myeloproliferative neoplasms (MPNs) is closely related to the acquisition of specific molecular alterations in JAK2, MPL, or CALR genes, the presence of which represent major diagnostic criteria in the WHO classification. The CALR exon 9 insertions and deletions are very heterogeneous, and their detection mainly relies on polymerase chain reaction (PCR) fragment length analysis.
We report on the rare nonclassical profiles that we observed among the 1382 patients analyzed by PCR fragment length analysis. In difficult cases, we tested germline DNA and performed NGS analysis.
We faced some troubling results because of the presence of several unexpected peaks. Our investigations showed that they resulted from a mix of isolated or double somatic mutations combined with germline alterations which could be misleading for a correct diagnosis. The precise interpretation of such difficult cases is mandatory as a misinterpretation could lead to the prescription of cytoreductive drugs to nondiseased persons or to an absence of treatment in true MPN patients.
Our observations showed that every mutation should be verified by direct Sanger sequencing, and we show that sometimes it may be necessary to study germline DNA and to complement with NGS analysis to precisely interpret the molecular alterations.
骨髓增殖性肿瘤（MPNs）的发病机制与 JAK2、MPL 或 CALR 基因获得特定的分子改变密切相关，这些改变的存在是世界卫生组织分类中的主要诊断标准。CALR 外显子 9 的插入和缺失非常多样，其检测主要依赖于聚合酶链反应（PCR）片段长度分析。
我们报告了通过 PCR 片段长度分析分析的 1382 例患者中观察到的罕见非典型谱。在困难的情况下，我们测试了种系 DNA 并进行了 NGS 分析。
由于存在多个意外峰，我们遇到了一些令人困扰的结果。我们的研究表明，这些结果是由孤立或双重体细胞突变与种系改变混合引起的，这可能会对正确诊断造成误导。对这些困难病例进行准确的解释是必要的，因为错误的解释可能导致对无疾病个体开具细胞减少药物或对真正的 MPN 患者缺乏治疗。
我们的观察表明，每个突变都应该通过直接 Sanger 测序进行验证，我们还表明，有时可能需要研究种系 DNA 并通过补充 NGS 分析来精确解释分子改变。
