W.K. Kellogg Eye Center, Department of Ophthalmology and Visual Science, University of Michigan, Ann Arbor, MI 48109, USA.
Center of Computational Medicine and Bioinformatics, University of Michigan, Ann Arbor, MI 48109, USA.
Int J Mol Sci. 2021 Sep 16;22(18):9992. doi: 10.3390/ijms22189992.
Primary Central Nervous System Lymphoma (PCNSL) is a lymphoid malignancy of the brain that occurs in ~1500 patients per year in the US. PCNSL can spread to the vitreous and retina, where it is known as vitreoretinal lymphoma (VRL). While confirmatory testing for diagnosis is dependent on invasive brain tissue or cerebrospinal fluid sampling, the ability to access the vitreous as a proximal biofluid for liquid biopsy to diagnose PCNSL is an attractive prospect given ease of access and minimization of risks and complications from other biopsy strategies. However, the extent to which VRL, previously considered genetically identical to PCNSL, resembles PCNSL in the same individual with respect to genetic alterations, diagnostic strategies, and precision-medicine based approaches has hitherto not been explored. Furthermore, the degree of intra-patient tumor genomic heterogeneity between the brain and vitreous sites has not been studied. In this work, we report on targeted DNA next-generation sequencing (NGS) of matched brain and vitreous samples in two patients who each harbored VRL and PCSNL. Our strategy showed enhanced sensitivity for molecular diagnosis confirmation over current clinically used vitreous liquid biopsy methods. We observed a clonal relationship between the eye and brain samples in both patients, which carried clonal deep deletions, a highly recurrent alteration in VRL patients, as well as p.L265P activating mutation in one patient. Several subclonal alterations, however, in the genes , , , and broad chromosomal regions showed heterogeneity between the brain and the eyes, between the two eyes, and among different regions of the PCNSL brain lesion. Taken together, our data show that NGS of vitreous liquid biopsies in PCNSL patients with VRL highlights shared and distinct genetic alterations that suggest a common origin for these lymphomas, but with additional site-specific alterations. Liquid biopsy of VRL accurately replicates the findings for PCNSL truncal (tumor-initiating) genomic alterations; it can also nominate precision medicine interventions and shows intra-patient heterogeneity in subclonal alterations. To the best of our knowledge, this study represents the first interrogation of genetic underpinnings of PCNSL with matched VRL samples. Our findings support continued investigation into the utility of vitreous liquid biopsy in precision diagnosis and treatment of PCNSL/VRL.
原发性中枢神经系统淋巴瘤（PCNSL）是一种脑内的淋巴细胞恶性肿瘤，在美国每年约有 1500 名患者发生该病。PCNSL 可播散至玻璃体和视网膜，在那里被称为眼内淋巴瘤（VRL）。虽然诊断的确认性检测依赖于对脑组织或脑脊液的有创性取样，但由于易于获取且相对于其他活检策略风险和并发症最小化，将玻璃体作为近端生物液体进行液体活检以诊断 PCNSL 是一种很有吸引力的前景。然而，以前认为与 PCNSL 完全相同的 VRL 在遗传改变、诊断策略和基于精准医学的方法方面与同一患者中的 PCNSL 有多大程度的相似性，迄今为止尚未得到探索。此外，脑内和玻璃体部位之间的患者内肿瘤基因组异质性程度尚未得到研究。在这项工作中，我们报告了对两名分别患有 VRL 和 PCSNL 的患者的匹配脑和玻璃体样本进行靶向 DNA 下一代测序（NGS）的结果。我们的策略显示出比当前临床上使用的玻璃体液体活检方法更高的分子诊断确认灵敏度。我们观察到这两名患者的眼部和脑部样本之间存在克隆关系，其中携带克隆性深度缺失，这是 VRL 患者中高度复发的改变，以及一名患者中的 p.L265P 激活突变。然而，在 、 、 和广泛的染色体区域的几个亚克隆改变中，在大脑和眼睛之间、两只眼睛之间以及 PCNSL 脑病变的不同区域之间表现出异质性。总的来说，我们的数据表明，对 VRL 合并 PCNSL 患者的玻璃体液体活检进行 NGS 突出了共同和独特的遗传改变，这些改变提示这些淋巴瘤具有共同起源，但存在额外的部位特异性改变。VRL 的液体活检准确复制了 PCNSL 主干（肿瘤起始）基因组改变的发现；它还可以提名精准医学干预，并显示患者内亚克隆改变的异质性。据我们所知，这项研究代表了首次对 VRL 匹配样本进行 PCNSL 遗传基础的研究。我们的研究结果支持进一步研究玻璃体液体活检在 PCNSL/VRL 精准诊断和治疗中的应用。
