Identification of Cell Surface Targets Based on Gene Amplification/Overexpression

在过去的几十年里，食道远端和胃食道交界处的腺癌的发病率以惊人的超过350%的速度增长。这是在所有癌症类型中观察到的发病率最大的增长之一。当这些癌症被及早发现时，患者在手术切除后有相对较好的结果。该病的血管和淋巴扩散迅速，临床对放疗和化疗的反应差，导致大多数患者预后不佳。尽管多模式治疗，食道癌的5年存活率仍然令人沮丧，只有5-15%(2，3)。这突显了开发新的方法对患有巴雷特化生等癌前病变的患者进行早期癌症检测的重要性，并改进新的治疗方式以提高这种致命疾病患者的存活率。 肠(Barrett‘s)化生的存在，即正常的鳞状黏膜 取而代之的是柱状上皮，与食管腺癌(2-6)有关。这种病是 肥胖人口增加，在美国和其他西方社会，这一人口迅速增长。在……里面 有胃酸反流症状的患者，首次内窥镜检查时(5，6)，Barrett‘s黏膜约占10-12%。据估计，患有巴雷特化生的患者罹患腺癌的风险是普通人群的30到40倍(3，4)。这种情况的恶性潜能可以从非发育不良的巴雷特化生发展为低度不典型增生、高度不典型增生，最后发展为浸润性腺癌。出于这个原因，已知的Barrett病患者要定期进行内窥镜检查。 目前，监测是通过白光内窥镜和随机四象限活检进行的。然而， 在食道，癌前病变是扁平的，在内窥镜下与肠化生不明显， 因此，该方法的灵敏度和特异度是有限的。此外，这种方法还没有被证明是 降低肠化生发展为腺癌的比率(7)，因此，一种新的治疗策略 巴雷特的食道监测是非常必要的。 虽然胃食道反流病(GERD)和化生改变的发展 公认的关键事件，许多特定的分子事件支持腺癌的发展 仍然不完全理解(2-6)。家族性因素可能是一种常染色体显性遗传模式，具有不完全外显，这一观点被认为是遗传易感性的基础[8]。 GERD的发展也可能反映了家族遗传的另一个方面，因为它比 与配偶对照相比，在受影响的兄弟姐妹和父母对中都很常见(9)。巨大的 在食管腺癌中检测到的分子异质性表明，患有Barrett化生并导致腺癌的个体可能存在多种途径或特定的转化事件组合。与食管下部腺癌和胃食道交界处的发展相关的事件似乎是相似的，并可能反映了相似的特征。 本申请中提出的研究结合了两种综合方法来解决 食管腺癌的临床问题日益突出。利用我们的SNP-阵列分析食道 腺癌，我们将首先搜索非随机DNA扩增谱系，它发生在 肿瘤类型。然后我们将确定定位在每个扩增的核心区内的基因和那些编码表面蛋白的基因。利用我们的Barrett化生无不典型增生、Barrett有低度不典型增生、高度不典型增生和浸润性腺癌的基因表达数据库，我们将定义那些在癌细胞中特异性过度表达的基因。组织芯片和免疫组织化学将用于验证候选基因蛋白的过度表达。经过验证的候选基因将在模型细胞系中被转染和过度表达，以使我们能够选择针对这些基因产物的特定多肽。当荧光标记时，这些多肽可以在常规内窥镜检查中局部注射到高危患者的食道上，以观察较大的表面积并指导组织活检。体内验证将按照项目2中的描述进行。这种方法有可能通过在癌症得到最有效治疗的时间点检测癌症来提高患者的存活率。我们现在相信，我们已经具备了针对日益严重的健康问题制定合理的应对计划的所有要素。

The incidence of adenocarcinoma of the distal esophagus and gastroesophageal junction has increased at an alarming rate of over 350% in the last few decades (1). This is among the greatest increase in incidence observed for any cancer type. When these cancers are detected early, patients have a relatively good outcome following surgical resection. The rapid vascular and lymphatic spread of this disease and the poor clinical response to radiation and chemotherapy, results in a poor outcome for most patients. Despite multimodal therapy, the 5-year survival rate for esophageal cancer remains dismal at only 5-15% (2,3). This highlights the importance of developing new methods for early cancer detection in patients with premalignant lesions such as Barrett's metaplasia and refining new treatment modalities to improve the survival of patients with this deadly disease. The presence of intestinal (Barrett's) metaplasia, a condition in which the normal squamous mucosa is replaced by columnar epithelium, is associated with esophageal adenocarcinoma (2-6). This disease is increased in obese individuals, a population rapidly expanding in the US and other Western societies. In patients with symptoms of acid reflux, Barrett's mucosa is found in ~10-12% at the time of initial endoscopy (5,6). Patients with Barrett's metaplasia have an estimated 30 to 40-fold greater risk of adenocarcinoma than the general population (3,4). The malignant potential of this condition is evidenced by the progression of non-dysplastic Barrett's metaplasia to low-grade dysplasia, high-grade dysplasia and finally to invasive adenocarcinoma. For this reason, patients with known Barrett's have regular endoscopic surveillance. Currently, surveillance is performed by white light endoscopy and random four-quadrant biopsy. However, in the esophagus, precancerous lesions are flat and endoscopically Indistinct from intesinal metaplasia, thus the sensitivity and specificity of this method is limited. Moreover, this method has not been shown to reduce the rate of progression of intestinal metaplasia to adenocarcinoma (7), thus, a new strategy for surveillance of Barrett's esophagus is critically needed. Although gastroesophageal reflux disease (GERD) and the development of metaplastic changes are recognized critical events, many specific molecular events underlying adenocarcinoma development remain incompletely understood (2-6). The idea that familial factors may be involved as an autosomaldominant pattern with incomplete penetrance has been hypothesized to underlie genetic predisposition (8). The development of GERD may also reflect another aspect of familial inheritance, as it is much more frequent in both affected sibling and parent pairs when compared to spouse controls (9). The tremendous molecular heterogeneity detected in esophageal adenocarcinomas suggests multiple pathways, or specific combinations of transforming events, may be occurring in individuals with Barrett's metaplasia and that lead to adenocarcinoma. The events associated with the development of both adenocarcinoma of the lower esophagus and the gastroesophageal junction, appear to be similar and may reflect the similar efiologies. The studies proposed in this application incorporate two integrated approaches to address the increasing clinical problem of esophageal adenocarcinoma. Using our SNP-array analyses of esophageal adenocarcinoma we will first search for the repertoire of nonrandom DNA amplification that occurs in this tumor type. We will then identify the genes localized within each amplified core region and those genes that encode surface proteins. Using our gene expression database for Barrett's metaplasia without dysplasia, Barrett's with low-grade dysplasia, high-grade dysplasia and invasive adenocarcinoma we will define those genes that are specifically over-expressed in cancer cells. Tissue microarrays and immunohistochemistry will be used to validate candidate gene protein over-expression. Validated candidate genes will be transfected and over-expressed in model cell lines to allow us to select specific peptides directed against these gene products. When fluorescently-labeled, these peptides can be topically administered onto the esophagus of high-risk patients during routine endoscopy to view large surface areas and to guide tissue biopsy. In vivo validation will be performed as described in Project 2. This approach has the potential to increase patient survival by detecting cancer at a point when it is most effectively treated. We now believe we have all of the components in place to make a rational plan of attack against a growing health problem.