Validation of potential early diagnostic and prognostic markers for pancreatic ca

描述（由申请人提供）：胰腺癌是发达国家第四大常见癌症死亡原因。不到10%的患者在诊断后存活超过1年，5年存活率（1-3%）是所有癌症中最低的。尽管胰腺癌的研究取得了进展，但患有这种毁灭性疾病的患者预后非常差。目前的化疗、放疗和外科手术在治疗这种疾病方面基本无效，因为大多数胰腺癌在诊断时已经进展为局部晚期不可切除或转移性疾病。该提案的目标是通过使用简单的非侵入性筛查测试来确定用于在早期阶段检测胰腺癌的标志物。当胰腺癌尚未达到晚期、不可切除或转移阶段时，可以通过使用治疗方法（如胰腺切除术加放化疗）来改善胰腺癌患者的生存率。最有前途的癌症早期诊断方法是利用肿瘤标志物。本研究采用不同的方法筛选正常胰腺癌与胰腺癌之间、非转移性胰腺癌细胞系与转移性胰腺癌细胞系之间的差异表达基因，发现γ-突触核蛋白和原肌球蛋白相关激酶B（Trk B）过表达。通过免疫印迹，可以在38%（56例中的21例）的胰腺癌患者血液样本中发现高水平的γ突触核蛋白，但在正常对照中则没有。TrkB在转移性人胰腺癌细胞中过表达，并与胰腺癌患者的肝转移相关。在拟议的研究中，我们将确定γ突触核蛋白是否是早期检测胰腺癌的潜在肿瘤标志物，通过开发更灵敏的检测方法，如ELISA，用于分析正常对照和胰腺癌及其他类型癌症患者的血液样本以及良性疾病如胰腺炎和肝炎的血清。我们将检查PanIN阶段中γ-突触核蛋白的表达。我们将通过将手术标本和内镜逆行胰胆管造影（ERCP）样本中TrkB免疫染色水平与胰腺癌的各个阶段相关联，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志物中所需的验证步骤，而不管在初始筛选中使用的技术。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，用于筛查无症状病例，从而在早期，局部和可治愈的阶段检测胰腺癌。我们的研究结果也可能提供胰腺癌转移的预后指标，并为胰腺癌患者的合理治疗提供方向，以及未来的临床研究所需的延长这些患者的生存期。

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.