Validating a novel biomarker of clinical progression and survival in CLL

描述（由申请人提供）：可以区分侵袭性和惰性形式的B细胞慢性淋巴细胞白血病（CLL）的预后标记物为该疾病的临床异质性提供了显著的见解，并影响了临床试验的设计，但分析这些指标的技术复杂性和可变性给医院实验室带来了挑战。该领域最重要的突破是发现CLL可以根据免疫球蛋白重链可变区（immunoglobulin heavy-chain variable region， IGHV）基因的体细胞高突变程度分为两大亚型，它们的临床侵袭性不同。IGHV基因突变个体（MT-CLL）的中位生存期是未突变IGHV基因（UM-CLL）患者的3倍。由于临床实验室对IGHV区域进行测序成本高昂且不切实际，大多数医院现在使用流式细胞术分析CD38和ZAP-70，因为它们在UM-CLL细胞中优先表达。尽管这两种蛋白都与不良预后显著相关，但它们与IGHV突变状态之间存在~25-30%的不一致性。此外，由于ZAP-70位于细胞质中，其染色可以变化，评估方案尚未标准化。长期目标是研究CLL的发病机制。该提案的总体目标是验证CLL预后的新型生物标志物的临床应用。我们的中心假设是Fc受体样2 （FCRL2）是惰性MT-CLL的独特指标，比其他目前使用的预后标志物更准确地预测IGHV突变状态和临床进展。这一假设基于：(i)我们最近发表的研究结果，即FCRL2强有力地预测了CLL的IGHV突变状态和临床进展，（ii）研究策略中概述的新开发的初步数据，以及（iii）其他研究者支持这一假设的独立工作。本研究的基本原理是，优化和验证FCRL2在CLL细胞上的检测将促进其广泛应用，并提高其相对于现有指标的预后准确性。我们计划通过以下具体目标来验证中心假设：1)通过流式细胞术优化FCRL2在CLL细胞上的检测；2)验证和确定FCRL2在预测IGHV突变状态、临床疾病进展和CLL生存中的预后效用。在Aim 1中，我们将优化新开发的检测FCRL2的试剂。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效用。这项拟议的研究具有创新性，因为它关注的是MT-CLL细胞中明显上调的表面受体，该受体与IGHV状态的一致性最高。这一贡献将是重要的，因为它将通过提高准确性、一致性、易用性和成本来推进CLL中目前建立的预测方法。FCRL2的使用将改变CLL诊断时的预后方法，当与其他标志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.