Validating a novel biomarker of clinical progression and survival in CLL

描述(申请人提供)：可以区分侵袭性和缓解性B细胞慢性淋巴细胞白血病(CLL)的预后标志物提供了对该疾病临床异质性的显著洞察，并正在影响临床试验的设计，但这些指标分析的技术复杂性和变异性给医院实验室带来了挑战。该领域最重大的突破是发现根据免疫球蛋白重链可变区(IGHV)基因的体细胞超突变程度，CLL可以分为两个主要亚型，它们的临床攻击性不同。携带突变IGHV基因的患者(MT-CLL)的中位生存期是携带未突变IGHV基因的患者(UM-CLL)的三倍。由于对IGHV区域进行测序不仅昂贵而且对临床实验室来说是不切实际的，鉴于CD38和ZAP-70在UM-CLL细胞中的优先表达，大多数医院现在使用流式细胞术来分析它们。虽然这两种蛋白都与预后不良密切相关，但它们与IGHV突变状态约有25%-30%的不一致性。此外，由于ZAP-70位于细胞质中，其染色可能会有所不同，评估它的方案还没有标准化。长期目标是研究CLL的发病机制。这项建议的总体目标是验证一种新的CLL预后生物标志物的临床实用性。我们的中心假设是Fc受体样2(FCRL2)是惰性MT-CLL的唯一指标，与目前使用的其他预后标志物相比，它将更准确地预测IGHV突变状态和临床进展。这一假设是基于：(I)我们最近发表的发现，FCRL2有力地预测了IGHV突变状态和CLL的临床进展，(Ii)研究战略中概述的新开发的初步数据，以及(Iii)支持这一假设的其他研究人员的独立工作。提出这项研究的基本原理是，对CLL细胞上FCRL2检测的优化和验证将促进其广泛应用，并提高现有指标的预后准确性。我们计划通过追求以下具体目标来检验中心假设：1)优化流式细胞术检测CLL细胞上FCRL2的方法；2)验证和定性FCRL2在预测IGHV突变状态、临床疾病进展和CLL生存方面的预后作用。在目标1中，我们将优化新开发的FCRL2检测试剂。在目标2中，我们将使用这些分析工具来验证FCRL2在预测IGHV突变状态和临床结果方面的有效性。这项拟议的研究具有创新性，因为它专注于MT-CLL细胞上明显上调的表面受体，该受体与IGHV状态具有最高的一致性。这一贡献将是重大的，因为它将通过提高准确性、一致性、易用性和成本来推进目前建立的CLL预测方法。FCRL2的使用将改变诊断时预测CLL的方法，与其他标记物一起使用时具有集体益处，并有望最终改变西方国家最常见白血病的临床治疗方法。

DESCRIPTION (provided by applicant): Prognostic markers that can discriminate between aggressive and indolent forms of B cell chronic lymphocytic leukemia (CLL) have provided remarkable insight into the clinical heterogeneity of the disease and are influencing the design of clinical trials, but the technical complexity and variability in assaying these indicators have presented challenges for hospital laboratories. The most significant breakthrough in the field was the discovery that CLL can be segregated into two major subtypes that differ in their clinical aggression according to the degree of somatic hypermutation in the immunoglobulin heavy-chain variable region (IGHV) gene. Individuals with mutated IGHV genes (MT-CLL) have a median survival that is three times longer than patients with unmutated IGHV genes (UM-CLL). Because sequencing IGHV regions is costly and impractical for clinical labs, most hospitals now analyze CD38 and ZAP-70 using flow cytometry given their preferential expression by UM-CLL cells. Although both proteins are significantly associated with a poor prognosis, they are ~25-30% discordant with IGHV mutation status. Furthermore, because ZAP-70 is located in the cytoplasm, its staining can vary and protocols to evaluate it are not yet standardized. The long term goal is to investigate the pathogenesis of CLL. The overall objective of this proposal is to validate the clinical utility of a novel biomarker of CLL prognosis. Our central hypothesis is that Fc receptor-like 2 (FCRL2), a unique indicator of indolent MT-CLL, will more accurately predict IGHV mutation status and clinical progression than other currently employed prognostic markers. This hypothesis is based on: (i) our recently published findings that FCRL2 robustly predicts IGHV mutation status and clinical progression in CLL, (ii) newly developed preliminary data outlined in the Research Strategy, and (iii) independent work by other investigators that supports this hypothesis. The rationale for the proposed research is that optimization and validation of FCRL2 detection on CLL cells will facilitate its wide application and improve prognostic accuracy over existing indicators. We plan to test the central hypothesis by pursuing the following specific aims: 1) Optimize the detection of FCRL2 on CLL cells by flow cytometry and 2) Validate and qualify the prognostic utility of FCRL2 in predicting IGHV mutation status, clinical disease progression, and survival in CLL. In Aim 1, we will optimize newly developed reagents for detecting FCRL2. In Aim 2, we will use these analytical tools to validate the utility of FCRL2 in predicting IGHV mutation status and clinical outcome. The proposed research is innovative, because it focuses on a surface receptor distinctly upregulated on MT-CLL cells that provides the highest concordance with IGHV status. This contribution will be significant because it will advance currently established approaches to prognostication in CLL by improving accuracy, consistency, ease of use, and cost. The use of FCRL2 will change the approach to CLL prognostication at diagnosis, have collective benefits when used with other markers, and is anticipated to ultimately modify approaches to clinical treatment in the most common leukemia in Western countries.