Sonobiopsy for Noninvasive Genetic Evaluation of Glioblastoma Patients

摘要 对于一种称为胶质母细胞瘤(GBM)的恶性脑肿瘤的遗传学和分子特性的非侵入性研究有着尚未得到满足的迫切需求。我们小组是第一个引入聚焦超声(FUS)的液体活组织检查技术，用于非侵入性和空间靶向的脑肿瘤分子诊断和特征，我们称之为声学。目前在临床实践中广泛使用声学检查的障碍是缺乏严格表征这项技术的安全性和可行性的人类数据。我们的长期目标是通过使用声学来提供疾病的遗传特征，从而改变GBM患者的临床管理。这项建议的总体目标是进行一项随机、双臂、单中心前瞻性临床试验，以验证声学检查的安全性和诊断可行性。我们有强有力的初步数据，证明了在啮齿动物和猪的GBM模型中进行声学检查的可行性和安全性，并开发了一种神经导航引导的FUS系统，用于对患者进行声学检查。拟议的临床试验将实现两个具体目标：1)证明声学检查将GBM血浆循环肿瘤DNA(CtDNA)浓缩到可检测的水平；2)确定GBM患者声学检查的安全性。在第一个目标下，我们将招募40名术前GBM患者，他们将被随机(1：1)进行声学检查和假手术。在手术切除前，立即进行声学检查或假手术，并在超声治疗前后采集血浆。将对血浆样本以及手术切除的超声肿瘤样本进行基因测序。我们将比较：1)声学检查前后血液中GBM特异性变异的频率，2)声学检查和假手术中ctDNA丰度的差异，3)声学检查后血浆样本和肿瘤样本标准测序在突变检测方面的一致性。对于第二个目标，由于超声检查或假干预将在手术切除前在术中MRI手术室中进行，我们将使用磁共振成像来确定血脑屏障通透性的变化，并检测周围健康组织和超声治疗部位的组织损伤或水肿/出血(如果发生)，将对手术切除的超声治疗和非超声治疗的肿瘤进行组织学分析，通过出血、坏死、细胞凋亡和炎症标记物的染色来确定超声治疗的安全性。该项目具有创新性，因为它以一种新颖的方式使用FUS大幅增加血液中肿瘤生物标记物的存在，从而大大偏离了现状。这项拟议的研究具有重要意义，因为它将建立知识基础，使这项创新技术的翻译成为可能，并最终通过识别肿瘤的基因特征来促进脑癌患者的诊断和监测。除了解剖成像和手术组织学的标准诊断外，声生物医学有可能成为脑肿瘤治疗的第三支柱，这将对患者的生存和生活质量产生巨大影响。

ABSTRACT There is an unmet critical need for noninvasive methods to interrogate the genetic and molecular properties of the malignant brain tumor known as glioblastoma (GBM). Our group was the first to introduce the focused ultrasound (FUS)-enabled liquid biopsy technique for noninvasive and spatially targeted molecular diagnosis and characterization of brain tumors, which we term sonobiopsy. The current barrier to the widespread use of sonobiopsy in clinical practice is the lack of human data that rigorously characterizes the safety and feasibility of this technique. Our long-term goal is to transform the clinical management of GBM patients by providing genetic signatures of the disease using sonobiopsy. The overall obiective of this proposal is to perform a randomized, blinded, double-armed, single-center prospective clinical trial to validate the safety and diagnostic feasibility of sonobiopsy. We have strong preliminary data that demonstrated the feasibility and safety of sonobiopsy in rodent and porcine GBM models and also developed a neuronavigation-guided FUS system for performing sonobiopsy in patients. The proposed clinical trial will accomplish two specific aims: 1) Demonstrate enrichment of GBM plasma circulating tumor DNA (ctDNA) to a detectable level with sonobiopsy and 2) Define the safety profile of sonobiopsy in GBM patients. Under the first aim, we will enroll forty presurgical GBM patients who will be randomized (1 :1) for sonobiopsy versus sham. Immediately prior to surgical resection, sonobiopsy or sham will be performed, and plasma will be collected pre- and post-sonication. Genetic sequencing will be performed on plasma samples, as well as surgically resected sonicated tumor samples. We will compare: 1) the frequency of GBM-specific variants in the blood pre- and post-sonobiopsy, 2) the differences in ctDNA enrichment between sonobiopsy and sham, and 3) the concordance in mutation detection between post-sonobiopsy plasma samples and standard sequencing of tumor samples. For the second aim, because the sonobiopsy or sham intervention will be performed in an intraoperative MRI surgical suite prior to resection, we will use MR imaging to define the blood-brain barrier permeability changes and detect tissue injury or edema/hemorrhage at the surrounding healthy tissue and sonicated sites if they occur, Histological analysis of surgically resected sonicated and un-sonicated tumors will be performed to define the safety profile of sonobiopsy by staining for hemorrhage, necrosis, apoptosis, and inflammation markers. This project is innovative because it is a substantial departure from the status quo by using FUS in a novel fashion to substantially increase the presence of tumor biomarkers in the blood. The proposed research is significant because it will establish the foundation of knowledge to enable the translation of this innovative technique and ultimately advance the diagnosis and monitoring of brain cancer patients by identifying genetic signatures of the tumor without surgery. In addition to the standard diagnostics of anatomic imaging and surgical histology, sonobiopsy has the potential to become the third pillar for brain tumor management which will have a dramatic impact on patient survival and quality of life.