Prognostic Models in Diffuse Large B-Cell Lymphoma

描述(申请人提供)：弥漫性大B细胞淋巴瘤(DLBCL)具有显著的生物学和临床异质性。在CHOP时代，已经证明可以通过测量有限数量的基因的表达来预测DLBCL患者的生存。然而，标准的治疗方法已经演变为包括美罗华和CHOP。初步研究表明，利妥昔单抗的加入改变了特定分子生物标记物的预测能力，可能与利妥昔单抗的抗肿瘤作用相关的新生物标记物可能在预后方面具有重要意义。因此，迫切需要为DLBCL患者建立可靠的基于生物标记物的预后模型，这可能会改变我们的行医方式。此外，以前的所有模型都是基于冰冻标本中的RNA测量，可用性有限，从而限制了所提出的预测模型的适用性。基于广泛可用的石蜡包埋样本构建预后模型，使用RNA或免疫组织化学分析基因表达，将使这些模型在日常临床实践中立即得到广泛应用。 该项目基于我们实验室开发的从福尔马林固定的石蜡包埋组织中提取RNA的新方法，该方法允许通过实时PCR或寡核苷酸微阵列可靠地测量基因表达。这一方法学将被用来完成本项目的目标，包括：1.通过基于阵列的基因表达谱确定与R-CHOP治疗的DLBCL患者的生存相关的基因表达列表；2.基于从石蜡标本中提取的RNA构建并验证基于石蜡标本的实时PCR基因表达预后模型；3.检测利妥昔单抗在R-CHOP治疗的DLBCL患者中的生存预测能力；4.基于免疫组织化学在蛋白质水平上测量的有限基因集的表达，构建R-CHOP治疗的DLBCL患者的预后模型。 这些研究应该为大多数常见类型的淋巴瘤定义基于石蜡的分子预后模型，这些模型将用于临床实践，并将增加当前临床预后指数的预后能力。预测模型的常规应用将能够识别出标准治疗失败的高危患者，并可能形成DLBCL风险调整治疗的基础。此外，识别组成预测模型的基因-蛋白质将指出DLBCL亚型的不同发病机制，并可能导致识别新的分子治疗靶点。此外，使用新的RNA提取方法建立基于石蜡的RNA预后模型可以作为其他淋巴瘤和肿瘤的范例。

DESCRIPTION (provided by applicant): Diffuse large B-cell lymphoma (DLBCL) is characterized by marked biological and clinical heterogeneity. In the CHOP-era, it was demonstrated that survival of DLBCL patients can be predicted by measurement of expression of a limited number of genes. However, the standard treatment has evolved to include the rituximab with CHOP. Initial studies suggest that addition of rituximab changes the predictive power of specific molecular biomarkers and it is possible that new biomarkers associated with the anti-tumor effects of rituximab may become prognostically significant. Therefore, there is an urgent need to establish reliable biomarker-based prognostic models for DLBCL patients treated with the current standard regimen of R-CHOP, which will potentially change the way we practice medicine. In addition, all the previous models were based on RNA measurement in frozen specimens, which availability is limited thus restricting applicability of the proposed prognostic models. Construction of prognostic models based on widely available paraffin embedded samples using either RNA or immunohistochemistry for analysis of gene expression would allow immediate and widespread applicability of these models in daily clinical practice. This project is based on a new methodology of RNA extraction from formalin-fixed, paraffin-embedded tissues, developed in our laboratory, which allows reliable measurement of gene expression by either real-time PCR or oligo-microarrays. This methodology will be used to accomplish the goals of this project that include: 1. Identify a list of genes which expression correlates with survival of DLBCL patients treated with R-CHOP by array-based gene expression profiling; 2. Construct and validate a paraffin-based real-time PCR gene expression prognostic mode based on RNA derived from paraffin specimens; 3. Examine the survival predictive power of biomarkers associated with the anti-tumor effects of rituximab in DLBCL patients treated with R-CHOP; 4. Construct a prognostic model for DLBCL patients treated with R-CHOP based on the expression of a limited set of genes measured at the protein level by immunohistochemistry. These studies should define paraffin-based molecular prognostic models for most common type of lymphoma that will be used in clinical practice and will add to the prognostic power of the current clinical prognostic indexes. Routine application of the prediction models will enable identification of patients at high risk for standard therapy failure and may form the basis for risk-adjusted therapies for DLBCL. Furthermore, identification of genes-proteins comprising the predictive models will point to distinct pathogenesis mechanisms of DLBCL subtypes and potentially lead to recognition of new molecular therapeutic targets. Further, establishment of a paraffin-based RNA prognostic model using the new methodology of RNA extraction could serve as a paradigm for other lymphomas and tumors.