Jovanovic Dragana, Markovic Jelena, Ceriman Vesna, Peric Jelena, Pavlovic Sonja, Soldatovic Ivan
Internal Medicine Clinic "Akta Medica", Belgrade, Serbia.
Pathology Department, Clinical Center of Serbia, Belgrade, Serbia.
J Thorac Dis. 2020 Dec;12(12):7561-7570. doi: 10.21037/jtd-2019-thym-13.
Thymic epithelial tumors (TETs) include several anterior mediastinal malignant tumours: thymomas, thymic carcinomas and thymic neuroendocrine cancers. There is significant variety in the biologic features and clinical course of TETs and many attempts have been made to identify target genes for successful therapy of TETs. Next generation sequencing (NGS) represents a huge advancement in diagnostics and these new molecular technologies revealed that thymic neoplasms have the lowest tumor mutation burden among all adult malignant tumours with a different pattern of molecular aberrations in thymomas and thymic carcinomas. As for the PD-L1 expression in tumor cells in thymoma and thymic carcinoma, it varies a lot in published studies, with findings of PD-L1 expression from 23% to 92% in thymoma and 36% to 100% in thymic carcinoma. When correlated PD-L1 expression with disease stage some controversial results were obtained, with no association with tumor stage in most studies. This is, at least in part, explained by the fact that several diverse PD-L1 immunohistochemical tests were used in each trial, with four different antibodies (SP142, SP263, 22C3, and 28-8), different definition of PD-L1 positivity and cutoff values throughout the studies as well. There is a huge interest in using genomic features to produce predictive genomic-based immunotherapy biomarkers, particularly since recent data suggest that certain tumor-specific genomic alterations, either individually or in combination, appear to influence immune checkpoint activity and better responses as the outcome, so as such in some cancer types they may complement existing biomarkers to improve the selection criteria for immunotherapy.
胸腺上皮肿瘤（TETs）包括几种前纵隔恶性肿瘤：胸腺瘤、胸腺癌和胸腺神经内分泌癌。TETs的生物学特征和临床病程存在显著差异，人们已进行了多次尝试以确定成功治疗TETs的靶基因。新一代测序（NGS）在诊断方面取得了巨大进展，这些新的分子技术显示，胸腺肿瘤在所有成人恶性肿瘤中具有最低的肿瘤突变负荷，胸腺瘤和胸腺癌的分子畸变模式不同。至于胸腺瘤和胸腺癌中肿瘤细胞的PD-L1表达，在已发表的研究中差异很大，胸腺瘤中PD-L1表达的研究结果为23%至92%，胸腺癌中为36%至100%。当将PD-L1表达与疾病分期相关联时，得到了一些有争议的结果，大多数研究中与肿瘤分期无关联。这至少部分是由于每个试验中使用了几种不同的PD-L1免疫组织化学检测方法，使用了四种不同的抗体（SP142、SP263、22C3和28-8），并且在整个研究中PD-L1阳性的定义和临界值也不同。利用基因组特征来产生基于预测基因组的免疫治疗生物标志物引起了极大的兴趣，特别是因为最近的数据表明，某些肿瘤特异性基因组改变，单独或联合起来，似乎会影响免疫检查点活性并产生更好的反应结果，因此在某些癌症类型中，它们可能补充现有的生物标志物以改善免疫治疗的选择标准。
