Intra-tumor Heterogeneity in Colorectal Cancer Progression and Treatment Response

项目总结： 结直肠癌(CRC)仍然是美国癌症相关死亡的第三大常见原因。 治疗取决于部位和分期，通常包括放射、化疗和手术。CRC 表型和对治疗的反应差异很大。CRCs的产生部分是由于体细胞的积累 突变和拷贝数变异(CNV‘s)。还没有发现完全可以预测的特定变化 表型。我们和其他人已经在CRC中发现了基因亚克隆。在其他类型的肿瘤中，最近的研究 都强调了遗传异质性在肿瘤表型中的潜在作用，但在结直肠癌中的作用 肿瘤进展和治疗反应中的异质性和肿瘤亚克隆仍不清楚。因此， 我们的假设如下：肿瘤内的遗传异质性在原发癌中很常见，并且 原发灶中存在的不同亚克隆支持结直肠癌的生物学行为和临床表型。 原发灶中不同的亚克隆可导致结直肠癌淋巴结(LN)和远处转移。该小组- 结直肠癌病变中出现的克隆对化疗和放射治疗的反应各不相同。三个具体的 提出的目标是解决总体假设：具体目标1：我们将描述 通过研究多个不同地理区域的体细胞遗传变化来研究CRC中遗传亚克隆的性质 AIMS 2和3中使用的每个肿瘤的区域。我们将使用生物信息学工具来整合突变和 CNV定义每个肿瘤内的基因亚克隆，并比较肿瘤之间的亚克隆。具体目标2： 比较20例原发结直肠癌患者与患者相匹配的LN转移癌患者的亚克隆。 确定亚克隆群体在转移进展中的作用的目标。我们提出的问题 答案是：1.转移到LNS的亚克隆是从大多数克隆还是少数克隆转移到 原发肿瘤？2.单个淋巴结转移是由单个亚克隆还是多个亚克隆组成？3.当有 单个患者的多发性淋巴结转移，它们是否来自原发肿瘤的同一亚克隆 肿瘤还是多个不同的亚克隆？具体目标3A：评估子克隆之间的关系 直肠癌患者术前放化疗反应与肿瘤的关系 治疗前后配对的原发直肠癌患者。我们假设某些直肠癌亚型- 克隆人对化疗和放射治疗敏感，其他克隆人对化疗和放射治疗耐药。目标3B：同时，我们将创造 20例直肠癌的异种移植模型，并评估它们是否模拟标准的反应 在匹配的患者中可以看到化疗和放射治疗。该提案将利用创新的排序和 生物信息学技术以及患者样本和临床信息。归根结底，更多的理解 对CRC进展和治疗反应背后的遗传机制的研究将使新的、有针对性的 有待提出和测试的治疗方法。该项目、多学科指导团队和教育计划 将使候选人成为结直肠癌遗传学领域的一名完全独立的研究员。

PROJECT SUMMARY: Colorectal cancer (CRC) remains the 3rd most common cause of cancer-related death in the United States. Treatment depends on location and stage and often includes radiation, chemotherapy and surgery. CRC phenotype and response to therapy vary significantly. CRCs arise in part due to the accumulation of somatic mutations and Copy Number Variants (CNV's). No particular change has been found that fully predicts phenotype. We and others have identified genetic sub-clones in CRC. In other tumor types, recent studies have highlighted the potential role of genetic heterogeneity in tumor phenotype, but in CRC the role of heterogeneity and tumor sub-clones in tumor progression and response to therapy remains unknown. Thus, we hypothesize the following: Substantial intra-tumoral genetic heterogeneity is common in primary CRCs, and the distinct sub-clones present in a primary lesion underpin CRC biological behavior and clinical phenotype. Distinct sub-clones in the primary lesion give rise to CRC lymph node (LN) and distant metastases. The sub- clones present in a CRC lesion vary in their response to chemotherapy and radiation therapy. Three specific aims are proposed to address the overarching hypotheses: Specific Aim 1: We will characterize the extent and nature of genetic sub-clones in CRCs by studying somatic genetic alterations in multiple, distinct geographic regions from each tumor used in aims 2 and 3. We will use bioinformatics tools to integrate mutations and CNV's to define genetic sub-clones within each tumor and compare sub-clones across tumors. Specific Aim 2: To compare sub-clones in primary CRC's to those in patient-matched LN metastases in 20 patients with the goal of defining the role of sub-clonal populations in metastatic progression. The questions we propose to answer are these: 1. Are the sub-clones that metastasize to the LNs from the majority or minority clones in the primary tumor? 2. Are individual LN metastasis made up of single or multiple sub-clones? 3. When there are multiple LN metastasis in an individual patient, are they derived from the same sub-clone from the primary tumor or multiple different sub-clones? Specific Aim 3A: To assess relationships between the sub-clones in the tumor and the response of rectal cancer patients to pre-operative chemotherapy and radiation, by analyzing 40 matched primary rectal cancers before and after treatment. We hypothesize that some rectal cancer sub- clones are sensitive and others resistant to chemo- and radiation therapy. Aim 3B: In parallel, we will create xenograft models of 20 of the rectal cancers and assess whether they mimic the response to standard chemotherapy and radiation seen in the matched patients. This proposal will utilize innovative sequencing and bioinformatics techniques along with patient samples and clinical information. Ultimately, greater understanding of the genetic mechanisms underlying CRC progression and response to treatment will allow novel, targeted therapies to be proposed and tested. This project, the multidisciplinary mentorship team, and educational plan will prepare the candidate to be a fully independent investigator in the field of colorectal cancer genetics.