Validation of potential early diagnostic and prognostic markers for pancreatic ca

描述(申请人提供)：胰腺癌是发达国家癌症死亡的第四大常见原因。只有不到10%的患者在确诊后存活超过一年，而5年生存率(1-3%)是所有癌症中最低的。尽管胰腺癌的研究取得了进展，但这种毁灭性疾病的患者预后非常差。目前的化疗、放射治疗和外科手术对这种疾病的治疗大多无效，因为大多数胰腺癌在确诊时已经发展为局部晚期的不能切除或转移的疾病。这项建议的目标是通过使用一种简单的非侵入性筛查测试来确定早期发现胰腺癌的标志物。当胰腺癌尚未达到进展期、无法切除或转移期时，采用胰腺十二指肠切除加放化疗等治疗方法可提高胰腺癌患者的生存率。最有希望的癌症早期诊断方法是利用肿瘤标记物。然而，同时具有高敏感性和高特异性的肿瘤标志物，特别是用于早期胰腺癌筛查和诊断的肿瘤标志物仍有待发现。通过采用不同的方法筛选正常胰腺癌和未转移胰腺癌细胞系之间的差异表达基因，鉴定了γ-突触核蛋白和原肌球蛋白相关激酶B(TrkB)的高表达。在胰腺癌患者的血液样本中，38%(21/56)可以通过免疫印迹检测到高水平的伽马突触核蛋白，但在正常对照中则不存在。TrkB在胰腺癌转移性细胞中高表达，并与胰腺癌肝转移相关。在这项拟议的研究中，我们会发展更灵敏的分析方法，例如酶联免疫吸附试验，以分析正常人、胰腺癌和其他癌症患者的血液样本，以及胰腺炎和肝炎等良性疾病的血清，以确定伽玛突触核蛋白是否可作为早期发现胰腺癌的潜在肿瘤标记物。我们将检测y-突触核蛋白在PanLN分期中的表达。我们将通过手术标本和内窥镜逆行胰胆管造影术(ERCP)标本的TrkB免疫标记水平与胰腺癌不同阶段的相关性来确定TrkB是否是胰腺癌转移的潜在预后标志物。我们提出的实验方法代表了在识别用于诊断和预后的肿瘤标记物方面所需的验证步骤，而不考虑在初始筛查中使用的技术。我们的研究可能会确定肿瘤标志物，以开发一种早期检测方法，用于无症状病例的筛查，以便在早期、局部和可治愈的阶段发现胰腺癌。我们的结果还可能为胰腺癌的转移提供一个预后指标，为胰腺癌患者的合理治疗以及未来延长患者生存所需的临床研究提供方向。

DESCRIPTION (provided by applicant): Pancreatic adenocarcinoma is the fourth most common cause of cancer death in the developed world. Less than 10% of patients survive for more than 1 year following diagnosis and the 5-year survival rate (1-3%) is the lowest of any cancer. Despite the advance in the research of pancreatic cancer, patients with this devastating disease have a very poor prognosis. Current chemotherapy, radiation therapy, and surgical procedures are largely ineffective in the treatment of this disease because most pancreatic cancers have already progressed into locally advanced unresectable or metastatic disease at the time of diagnosis. The goal of this proposal is to identify markers for detecting pancreatic cancer at an early stage by using a simple non-invasive screening test. When pancreatic cancer has not reached to advance, unresectable or metastatic stages, survival of patients with pancreatic cancer can be improved by using therapeutic approaches such as pancreaticoduodenectomy plus chemoradiation. The most promising approach for the early diagnosis of cancer utilizes tumor markers. However, tumor marker with both high sensitivity and high specificity, especially for screening and diagnosis of early stages of pancreatic cancer remains to be found. By using different approaches for screening differentially expressed genes between the normal and pancreatic tumor and between nonmetastatic and metastatic pancreatic tumor cell lines, overexpression of gamma synuclein and tropomyosin-related kinase B (TrkB) was identified. High levels of gamma synuclein can be found by immunoblotting in 38% (21 of 56) of blood samples from pancreatic cancer patients, but not in normal controls. Overexpression of TrkB was found in metastatic human pancreatic cancer cells and correlated with liver metastasis in pancreatic cancer patients. In the proposed study, we will determine whether gamma synuclein is a potential tumor marker for early detection of pancreatic cancer by developing more sensitive assays such as ELISA for analyzing blood samples from normal controls and patients with pancreatic cancer and other type of cancers as well as sera from benign diseases such as pancreatitis and hepatitis. We will examine the expression of y-synuclein in PanlN stages. We will determine whether TrkB is a potential prognostic marker for pancreatic cancer metastasis by correlating the levels of TrkB immunostaings from surgical specimens and endoscopic retrograde cholangiopancreatography (ERCP) samples with the various stages of pancreatic cancer. Our proposed experimental approaches represent the required verification step in identification of tumor marker for diagnosis and prognosis regardless of the techniques used in the initial screening. Our study may identify the tumor markers for developing an early detection method for screening of asymptomatic cases to detect pancreatic cancer at an early, localized, and curable stage. Our results may also provide a prognostic marker for metastasis of pancreatic cancer and a direction for the rational treatment of patients with pancreatic cancer, and the future clinical studies required to extend the survival of these patients.