Biological Definition of FCRL Molecules in Malignancy

描述(申请人提供)：B细胞慢性淋巴细胞白血病(B-CLL)是西方国家最常见的白血病，具有免疫球蛋白重链可变区(IgVH)基因突变状态不同的两种亚型的特点。虽然携带突变的IgVH基因(MT-CLL)的患者通常在最少的治疗干预下具有超过25年的无痛病程，但携带未突变的IgVH基因(UM-CLL)的患者经历了更具侵略性的过程，即使在强化治疗后，中位生存期仍为8年。尽管有这些差异，B-CLL细胞在转录和表型上与记忆B细胞相似。由于对大多数临床实验室来说，对IgVH区进行基因分型既昂贵又具有技术挑战性，目前正在研究突变状态的替代标记。研究发现，ZAP-70 Syk家族酪氨酸激酶的表达与UM-CLL的相关性最好，使患者能够分成惰性或更具侵袭性的队列；然而，通过流式细胞仪分析这一细胞质标记物带来了技术挑战，导致诊断的差异性。一类具有独特B细胞表达和酪氨酸信号转导功能的Fc受体样分子(FCRL1-5)的发现开辟了一个新的研究领域。我们研究的长期目标是确定FCRL分子在正常免疫中的生物学作用，并研究它们的功能如何在恶性肿瘤中被颠覆。我们的初步数据表明，五个FCRL蛋白中的四个在MT-CLL上优先过表达。值得注意的是，流式细胞术分析FCRL2在&gt；100 UM-CLL和MT-CLL细胞样本上的表面表达表明与MT-CLL具有很强的一致性，并具有预测早期治疗时间的能力。我们假设FCRL2可作为B-CLL的替代预后标志物，FCRL2细胞表面表达的流式细胞术分析不仅将为临床实验室提供可靠的检测方法，而且将扩大B-CLL的诊断能力。这将在两个具体目标中进行测试：1)通过流式细胞仪优化B-CLL细胞上FCRL2的检测并使其标准化；以及2)内部和外部验证FCRL2表达对预测B-CLL中IgVH突变状态和疾病进展的预后重要性。意义：用常规的临床流式细胞仪检测FCRL2的表面表达可以极大地改善B-CLL的预后，从而显著改善这种白血病患者的整体护理。此外，我们预计这些研究将通过提供关于侵袭性亚型的新见解来扩展B-CLL预后的能力，这最终可能有助于确定最佳治疗干预时机。公共卫生相关性：这项建议将调查最近描述的Fc受体样分子家族(FCRL)在西方国家最常见的白血病-B细胞慢性淋巴细胞白血病(B-CLL)中的表达。FCRL蛋白似乎在疾病的惰性形式中优先过度表达。这项工作将调查这些分子中的一些是否可以作为B-CLL的新的预后标志物，并取代或补充当前的疾病侵袭性指标。

DESCRIPTION (provided by applicant): B cell chronic lymphocytic leukemia (B-CLL), the most prevalent leukemia in Western countries, is characterized by two subtypes that differ in the mutation status of their immunoglobulin heavy-chain variable region (IgVH) gene. While patients with mutated IgVH genes (MT-CLL) typically have an indolent disease course of greater than 25 years with minimal therapeutic intervention, individuals harboring unmutated IgVH genes (UM-CLL) experience a more aggressive process with a median survival of 8 years even after intensive treatment. Despite these differences, B-CLL cells transcriptionally and phenotypically resemble memory B lineage cells. As genotyping of IgVH regions is costly and technically challenging for most clinical laboratories, surrogate markers for mutation status are being investigated. Expression of the ZAP-70 Syk family tyrosine kinase was found to best correlate with UM-CLL, enabling the stratification of patients into indolent or more aggressive cohorts; however, analysis of this cytoplasmic marker by flow cytometry has created technical challenges resulting in diagnostic variability. The identification of a family of Fc receptor-like molecules (FCRL1-5) with distinct B cell expression and tyrosine-based signaling function opens a new field of study. The long term goal of our studies is to determine the biological role of FCRL molecules in normal immunity and investigate how their functions may be subverted in malignancy. Our preliminary data indicate preferential overexpression of four of five FCRL proteins on MT-CLL. Notably, flow cytometric analysis of the surface expression of FCRL2 on >100 UM-CLL and MT-CLL cell samples indicated strong concordance with MT-CLL and an ability to predict early time to therapy. We hypothesize that FCRL2 can be used as a surrogate prognostic marker in B-CLL and that flow cytometric analysis of cell surface expression of FCRL2 will not only provide a robust assay suitable for clinical laboratories, but will also extend the capabilities of B-CLL diagnosis. This will be tested in two Specific Aims: 1) Optimization of FCRL2 detection on B-CLL cells by flow cytometry and standardization of the assay; and 2) Internal and external validation of the prognostic importance of FCRL2 expression for predicting IgVH mutation status and disease progression in B-CLL. Significance: The assessment of FCRL2 surface expression using routine clinical flow cytometry assays could greatly facilitate prognosis in B-CLL and, thus, significantly improve the overall care of patients with this leukemia. In addition, we anticipate that these studies will extend the capabilities of B-CLL prognosis by providing new insights concerning the aggressive subtype, which ultimately could assist in determination of the optimal timing of therapeutic intervention. PUBLIC HEALTH RELEVANCE: This proposal will investigate the expression of a recently described family of Fc receptor-like molecules (FCRL) in the most prevalent leukemia in Western countries, B cell chronic lymphocytic leukemia (B-CLL). FCRL proteins appear to be preferentially overexpressed in the indolent form of the disease. This work will investigate whether some of these molecules may serve as novel prognostic markers in B-CLL and replace or supplement current indicators of disease aggressiveness.