Mitochondrial biomarkers for early detection of cancer in ulcerative colitis

描述(申请人提供)：结直肠癌是溃疡性结肠炎(UC)最可怕的并发症之一，UC是一种炎症性肠道疾病，在美国有50多万人受到影响。为了降低癌症发病率和死亡率，患者 UC患者每1-2年进行一次结肠镜检查，以监测癌前病变。UC的肿瘤发生是一个多步骤的过程，包括低度不典型增生(LGD)、高度不典型增生(HGD)和癌症的进展。因为UC的不典型增生通常是平坦的，很难检测到，所以在结肠镜检查时，每10厘米的结肠取4象限的活检进行组织学评估。患有HGD或癌症的患者接受结肠切除术。LGD患者每3-6个月接受一次结肠切除术，如果是多灶性，则每隔3-6个月重复一次结肠镜检查。这种密集的监测方案既耗时又昂贵，而且发现异型增生的灵敏度有限。UC的患病率正在增加，但UC的癌症进展风险正在降低，这一事实加剧了该系统的局限性。因此，寻找生物标记物来检测谁是癌症高危患者比以往任何时候都更加关键，以便临床资源可以定向到他们身上，同时减少大多数患者的焦虑和结肠镜检查，而不会增加癌症风险。我们之前已经证明，通过分析存在于大的非发育异常区域中的分子变化可以识别出有癌症风险的患者，这些区域环绕着发育不良的病灶，通常会扩大到累及整个结肠。然而，之前的生物标记物未能进入临床，因为它们基于依赖冰冻活检的技术，而冰冻活检无法大量用于进行必要的验证研究。在这项提案中，我们提供了强有力的初步数据，证明线粒体变化发生在异型增生之前的大的非发育不良区域，并可以通过免疫组织化学和NanoString(一种允许对mRNA表达进行数字计数的新技术)在福尔马林固定的石蜡包埋(FFPE)活检组织中检测到。我们的目标是根据EDRN阶段的生物标志物开发，基于这两种技术开发线粒体生物标志物。第一阶段包括生物标记物的训练，将在AIM 1中通过免疫组织化学对线粒体蛋白进行训练，在AIM 2中通过纳米串对线粒体基因表达进行训练。生物标记物将被设计为通过分析仅3-6例来自患有HGD或癌症(进展)的UC患者和无异型增生的UC患者(非进展)的随机结肠活检来检测HGD或结肠其他部位癌症的存在。在目标3中，我们将在一组独立的患者中验证这些生物标志物。在目标4中，我们将测试生物标记物预测非发育不良或LGD活检患者进展为癌症的能力。这些研究可能会产生一种有用且亟需的UC癌症风险生物标记物，其他小组可以使用存档的FFPE材料复制该标记物，以完成其验证和快速转换到临床。

DESCRIPTION (provided by applicant): Colorectal cancer is one of the most feared complications of ulcerative colitis (UC), an inflammatory bowel disease that affects more than half a million individuals in the United States. To reduce cancer morbidity and mortality, patients with UC undergo colonoscopies every 1-2 years to monitor precancerous dysplasia. Tumorigenesis in UC is a multistep process that involves progression through low-grade dysplasia (LGD), high-grade dysplasia (HGD), and cancer. Because dysplasia in UC is often flat and difficult to detect, 4-quadrant biopsies from every 10cm of colon are taken at colonoscopy to be histologically evaluated. Patients with HGD or cancer undergo colectomy. Patients with LGD undergo colectomy, if multifocal, or repeated colonoscopies every 3-6 months, if unifocal. This intensive surveillance protocol is time-consuming, expensive, and of limited sensitivity to find dysplasia. The limitations of this system are aggravated by the fact that the prevalence of UC is increasing, but the risk of cancer progression in UC is decreasing. Thus, it is more crucial than ever to find biomarkers to detect who are the patients at high risk of cancer, so that clinical resources can be directed to them, while reducing anxiety and colonoscopies for the majority of patients without increased cancer risk. We have previously demonstrated that the patients at risk of cancer can be identified by analyzing molecular alterations that are present in large, non-dysplastic fields that surround dysplastic foci and often expand to involve the whole colon. Previous biomarkers, however, failed to reach the clinic because they were based on techniques that rely on frozen biopsies, which are not available in large numbers to perform the necessary validations studies. In this proposal, we present strong preliminary data that demonstrates that mitochondrial alterations occur in large, non-dysplastic fields that precede dysplasia, and can be detected in formalin-fixed, paraffin-embedded (FFPE) biopsies by immunohistochemistry and Nanostring, a novel technology that allows digital counting of mRNA expression. Our goal is to develop mitochondrial biomarkers based on these two techniques according to the EDRN phases for biomarker development. Phase I consists on the training of the biomarker and it will be performed for mitochondrial proteins by immunohistochemistry in Aim 1 and for mitochondrial gene expression by Nanostring in Aim 2. The biomarkers will be designed to detect the presence of HGD or cancer elsewhere in the colon by analyzing only 3-6 random colon biopsies from UC patients with HGD or cancer (Progressors) and UC patients dysplasia-free (Non Progressors). In Aim 3, we will validate the biomarkers in an independent set of patients. In Aim 4 we will test the ability of the biomarkers to predict progression to cancr in patients with non-dysplastic or LGD biopsies. These studies are likely to produce a useful and much needed biomarker of cancer risk in UC, which could be replicated by other groups using archival FFPE material in order to complete its validation and quick translation to the clinic.