INSERM U955 Équipe 9, Institut Mondor de Recherche Biomédicale, Créteil, France; Université Paris Est, Créteil, France.
INSERM U955 Équipe 9, Institut Mondor de Recherche Biomédicale, Créteil, France; Université Paris Est, Créteil, France; Unité Hémopathies Lymphoïdes, Assistance Publique-Hôpitaux de Paris, Hôpital Henri Mondor, Créteil, France.
J Mol Diagn. 2018 Sep;20(5):677-685. doi: 10.1016/j.jmoldx.2018.05.012. Epub 2018 Jul 5.
Angioimmunoblastic T-cell lymphoma (AITL) is a peripheral T-cell lymphoma associated with chemoresistance and a poor prognosis. Various nonsynonymous mutations in the R172 residue of IDH2 are present in 20% to 30% of AITL patients. In addition to their diagnostic value, these mutations are potentially targetable, especially by isocitrate dehydrogenase (IDH) 2 inhibitor, and therefore their identification in a routine setting is clinically relevant. However, in AITL, the neoplastic cells may be scarce, making the identification of molecular anomalies difficult. We evaluated the diagnostic value of different methods to detect IDH2 mutations in formalin-fixed, paraffin-embedded tumor samples. Immunohistochemistry with an anti-IDH2 R172K antibody, Sanger sequencing, high-resolution melting PCR, allele-specific real-time quantitative PCR, and next-generation sequencing (NGS) were applied to biopsy specimens from 42 AITL patients. We demonstrate that the IDH2 R172K antibody is specific to this amino acid substitution and highly sensitive for the detection of the IDH2 variant, the most frequent substitution in this disease. In our study, NGS and allele-specific real-time quantitative PCR displayed a good sensitivity, detecting 96% and 92% of IDH2 mutations, respectively, in contrast to Sanger sequencing and high-resolution melting PCR, which showed a significantly lower detection rate (58% and 42%, respectively). These results suggest that a combination of immunohistochemistry and AS-PCR or NGS should be considered for the identification of IDH2 mutations in AITL in a routine setting.
血管免疫母细胞性 T 细胞淋巴瘤（AITL）是一种与化疗耐药和预后不良相关的外周 T 细胞淋巴瘤。在 20% 至 30%的 AITL 患者中存在 IDH2 的 R172 残基的各种非同义突变。除了具有诊断价值外，这些突变可能是可靶向的，尤其是针对异柠檬酸脱氢酶（IDH）2 抑制剂，因此在常规环境中识别它们具有临床相关性。然而，在 AITL 中，肿瘤细胞可能很少，使得鉴定分子异常变得困难。我们评估了不同方法在福尔马林固定、石蜡包埋的肿瘤样本中检测 IDH2 突变的诊断价值。应用抗 IDH2 R172K 抗体免疫组化、Sanger 测序、高分辨率熔解 PCR、等位基因特异性实时定量 PCR 和下一代测序（NGS）对 42 例 AITL 患者的活检标本进行了检测。我们证明 IDH2 R172K 抗体特异性针对该氨基酸取代，对 IDH2 变体的检测具有高度敏感性，IDH2 变体是该疾病中最常见的取代。在我们的研究中，NGS 和等位基因特异性实时定量 PCR 的敏感性分别为 96%和 92%，而 Sanger 测序和高分辨率熔解 PCR 的检测率显著较低（分别为 58%和 42%）。这些结果表明，在常规环境中，免疫组化和 AS-PCR 或 NGS 的组合应考虑用于鉴定 AITL 中的 IDH2 突变。
