Cancer specific expression of Cathepsin E in pancreas

胰腺导管癌经常表达胃肠道上皮细胞的标记物。组织蛋白酶E （CTSE）是一种非分泌性、细胞内但非溶酶体的蛋白酶，在胃浅表上皮细胞中浓度最高。本研究的目的是检测胰腺中CTSE的表达，建立CTSE检测系统，并评价胰液中CTSE的诊断价值。11例胰腺导管腺癌，10例产生黏液腺瘤，3例导管内乳头状增生，43例慢性胰腺炎。手术切除胰腺组织行CTSE免疫组化。收集患者胰液，采用夹心酶联免疫吸附试验（ELISA）和western分析法检测CTSE。胰腺导管腺癌CTSE免疫组化染色阳性。CTSE在产生黏液的腺瘤、导管内乳头状增生和黏液增生中也有表达。11例胰管腺癌患者中有8例（72.7%）、10例产粘蛋白肿瘤患者中有5例（50%）、3例导管内乳头状增生患者中有1例（33.3%）、43例慢性胰腺炎患者中有4例（9.3%）胰腺液中有CTSE。胰腺导管腺癌患者胰液中CTSE的检出率明显高于慢性胰腺炎患者。这些结果提示CTSE的表达与胰腺导管腺癌的发病机制有关，胰液中的CTSE似乎是明确诊断的有用标志物，CTSE可能在胰腺病变多步骤癌变的相对早期表达。

Ductal cancers of the pancreas frequently express markers of gastrointestinal epithelial cells. Cathepsin E (CTSE) is a non-secretory, intracellular, but non-lysosomal proteinase found in the highest concentration in the superficial epithelial cells of the stomach. The aims of the present study were to examine the expression of CTSE in the pancreas, to establish an assay system of CTSE,and to evaluate the diagnostic usefulness of CTSE in the pancreatic juice. Eleven patients with pancreatic ductal adenocarcinoma, 10 with mucin-producing adenoma, 3 with intraductal papillary hyperplasia, and 43 with chronic pancreatitis were examined. Surgically resected pancreatic tissues were subjected to the immunohistochemistry for CTSE.Pancreatic juice was collected from the patients, and subjected to sandwich enzyme-linked immunosorbent assay (ELISA) and Westem analysis for detecting CTSE.Positive staining for CTSE was observed in pancreatic ductal adenocarcinoma by immunohistochemistry. CTSE was also expressed in mucin-producing adenoma, intraductal papillary hyperplasia, and mucinous hyperplasia. CTSE in the pancreatic juice was present in 8 of 11 patients with pancreatic ductal adenocarcinoma (72.7%), 5 of 10 patients with mucin-producing tumor (50%), 1 of 3 patients with intraductal papillary hyperplasis (33.3%), and 4 of 43 patients with chronic pancreatitis (9.3%). The detection frequency of CTSE in the pancreatic juice was significantly higher in the patients with pancreatic ductal adenocarcinoma than in the patients with chronic pancreatitis. These findings suggest that the expresson of CTSE is associated with the pathogenesis of pancreatic ductal adenocarcinoma, CTSE in the pancreatic juice seems to be a useful marker for the definitive diagnosis, and the CTSE may be expressed at a relatively early stage of multistep carcinogenesis in the pancreas lesions.