Minoru Fujino

Analysis of risk factors for recurrence after curative resection of well-differentiated pancreatic neuroendocrine tumors based on the new grading classification

It is difficult to predict the malignant potential of pancreatic neuroendocrine tumors (PNETs) precisely. This study investigated the validity of a new grading system adopted by the World Health Organization 2010 classification to determine risk factors for recurrence of PNETs.

Anterior gradient 2 downregulation in a subset of pancreatic ductal adenocarcinoma is a prognostic factor indicative of epithelial–mesenchymal transition

Anterior gradient 2 (AGR2), a member of the protein disulfide isomerase family, has been implicated in various cancers including pancreatic ductal adenocarcinoma (PDAC) and is known to promote cancer progression. However, the prognostic value of AGR2 expression and the interaction with epithelial–mesenchymal transition (EMT) remain unclear. We investigated the clinical significance of AGR2 and EMT markers in PDAC patients by immunohistochemical analyses. Although AGR2 expression was not observed in normal pancreas, all pancreatic precursor neoplastic lesions were positive for AGR2, even at the earliest stages, including pancreatic intraepithelial neoplasia-1A, AGR2 expression was reduced in 27.7% (54/195 cases) of PDAC patients. AGR2 downregulation correlated with EMT markers (vimentin overexpression and reduced membranous E-cadherin expression), high Union for International Cancer Control stage (P<0.0001), high histological cellular grade (P<0.0001), and adverse outcome (P<0.0001). In vitro, targeted silencing of AGR2 in cancer cells using siRNA reduced cell proliferation, colony formation, cell invasiveness, and migration, but did not alter EMT markers. To confer a more aggressive phenotype and induce EMT in PDAC cells, we co-cultured PDAC cell lines with primary-cultured pancreatic stellate cells (PSCs) and found that AGR2 was downregulated in co-cultured PDAC cells compared with PDAC monocultures. Treatment with transforming growth factor beta-1 (TGF-β), secreted from PSCs, decreased AGR2 expression, whereas inhibition of TGF-β signaling using recombinant soluble human TGF-β receptor type II and TGF-β-neutralizing antibodies restored AGR2 expression. We conclude that AGR2 downregulation is a useful prognostic marker, induced by EMT, and that secreted TGF-β from PSCs may partially contribute to AGR2 downregulation in PDAC patients. AGR2 downregulation does not induce EMT or a more aggressive phenotype, but is a secondary effect of these processes in advanced PDAC.

Insulin-like growth factor II messenger RNA-binding protein-3 is a valuable diagnostic and prognostic marker of intraductal papillary mucinous neoplasm.

Recently, various studies have shown that insulin-like growth factor II messenger RNA-binding protein-3 (IMP3) is a useful diagnostic marker for malignant lesions and a prognostic marker for poor survival in several kinds of tumors. However, the value of IMP3 as a diagnostic and prognostic marker in intraductal papillary mucinous neoplasm (IPMN) of pancreas has been unclear until now. In this study, we examined IMP3 immunohistochemical expression in 190 resection samples and 15 biopsy samples of IPMN and analyzed the value of IMP3 as a diagnostic and prognostic marker. IMP3 expression was recognized in 71.8% (28/39) of IPMNs with high-grade dysplasia and in 81.3% (26/32) of IPMNs with an associated invasive carcinoma (IPMN-IC), but it was not found in any IPMNs with low-grade dysplasia or in IPMNs with intermediate dysplasia. IMP3 expression was significantly higher in cancerous lesions (IPMN with high-grade dysplasia and IPMN-IC) than in noncancerous lesions (IPMN with low-grade dysplasia and IPMN with intermediate-grade dysplasia), with a sensitivity of 76.1% and a specificity of 100% (P < .001). We also identified a significant difference in IMP3 expression between cancerous lesions and noncancerous lesions in biopsy specimens (P = .027). In IPMN-IC, disease-specific survival was significantly shorter in the high-expression group (>50% tumor staining) than in the low-expression group (≤50% tumor staining; P = .0069). In conclusion, our findings show that IMP3 is a useful diagnostic marker for distinguishing between noncancerous and cancerous lesions and is a valuable prognostic biomarker in IPMN.

Differential ezrin and phosphorylated ezrin expression profiles between pancreatic intraepithelial neoplasia, intraductal papillary mucinous neoplasm, and invasive ductal carcinoma of the pancreas

Intraductal papillary mucinous neoplasms (IPMNs) and pancreatic intraepithelial neoplasia (PanINs) are important premalignant lesions of pancreatic cancer. Ezrin is a member of the ezrin, radixin, and moesin protein family and acts as a cross-linker between the plasma membrane and the actin cytoskeleton. We investigated the roles of ezrin during carcinogenesis in IPMN and invasive ductal carcinoma and examined whether ezrin was a prognostic factor. We examined ezrin and phosphorylated ezrin (p-ezrin) expression in 131 IPMNs, 47 PanINs, and 59 invasive ductal carcinomas by immunohistochemical staining. Ezrin and p-ezrin (tyr354) expressions were significantly higher in IPMN with an associated invasive carcinoma, compared with those in IPMN with high-grade dysplasia (P = .03 and P = .0007, respectively). In all grades of PanINs, ezrin and p-ezrin (tyr353) were highly expressed. In patients with invasive ductal carcinoma, the presence of PanIN-2 or PanIN-3 was significantly correlated with positive ezrin and p-ezrin (tyr353) expression of the invasive ductal carcinoma component (P = .01 and P = .0004). The negative p-ezrin (tyr353) expression group of invasive ductal carcinoma showed a significantly worse prognosis than did the positive p-ezrin (tyr353) expression group by survival analysis (P = .04) and was a statistically significant adverse prognostic factor by both univariate and multivariate analyses (P = .048 and P = .015). Ezrin phosphorylation sites differ between the developments of IPMN and PanIN. Although p-ezrin (tyr354) expression in IPMNs is associated with tumor invasion, p-ezrin (tyr353) expression in invasive ductal carcinoma plays an important role not in tumor invasion and metastasis but in the early development of PanINs.

Expression of glucagon-like Peptide 1 receptor and its effects on biologic behavior in pancreatic neuroendocrine tumors.

Objectives Glucagon-like peptide 1 (GLP-1) interacts with its specific high-affinity receptor, glucagon-like peptide 1 receptor (GLP-1R), and induces cellular growth and inhibition of apoptosis in pancreatic &bgr; cells. The aim of this study was to investigate the significance of GLP-1R expression in pancreatic neuroendocrine tumors (PNETs). Methods Glucagon-like peptide 1 receptor expression was semiquantitatively evaluated by immunohistochemical staining in 50 resected PNETs, and the correlation between the GLP-1R expression and clinicopathologic features was investigated. Results There were 23 PNETs with positive expression and 27 PNETs with negative expression of GLP-1R. Positive expression of GLP-1R was more frequently observed in insulinoma than in gastrinoma and nonfunctioning tumor (P < 0.05). Although expression status of GLP-1R did not affect the prognosis of the patients with PNETs (P = 0.82), most of the metastatic sites such as lymph node and liver showed positive staining for GLP-1R (8 of 11 PNETs, 73%). Conclusions Glucagon-like peptide 1 receptor would be a diagnostic marker of insulinoma and might become a molecular target for treatment of metastatic PNETs and hormonal regulation of insulin.

Pancreatic intraepithelial neoplasia in the background of invasive ductal carcinoma of the pancreas as a prognostic factor.

Of the recognized precursor lesions of pancreatic adenocarcinoma, pancreatic intraepithelial neoplasia (PanIN) is the most common form. However, little is known about the relationship between the grade of PanIN and prognosis for patients with invasive ductal carcinoma.

Expression of glucose transporter-1 is correlated with hypoxia-inducible factor 1α and malignant potential in pancreatic neuroendocrine tumors

The present study aimed to investigate the prognostic usefulness of the expression of glucose transporter type 1 (GLUT-1) and GLUT-2, hypoxia-inducible factor 1α (HIF-1α) and insulin-like growth factor II messenger RNA-binding protein 3 (IMP3) in pancreatic neuroendocrine tumors (pNETs). Immunohistochemical staining for GLUT-1, GLUT-2, HIF-1α and IMP3 was performed in 70 pNET specimens. The expression of GLUT-1 and HIF-1α was significantly higher in the World Health Organization grade 2 (G2), neuroendocrine carcinoma cases and mixed-type pNETs compared with the G1 cases. Vessel invasion, a high Ki-67 labeling index and a high mitotic count were significantly more frequent in the GLUT-1- and HIF-1α-positive cases compared with the negative cases. Lymph node metastasis was significantly higher in the GLUT-1-positive cases than in the negative cases. Insulin expression was significantly higher in the IMP3-positive cases than the negative cases. The GLUT-1 expression group experienced a significantly poor disease-free survival rate compared with the negative GLUT-1 expression group. HIF-1α expression was significantly correlated with poor disease-free survival and overall survival rates. A multivariate analysis revealed that lymph node metastasis was an independent risk factor for disease-free survival in all cases. In the G1/G2 group, tumor size and lymph node metastasis were independent risk factors for disease-free survival. Overall, the results suggested that GLUT-1 is a useful prognostic biomarker for pNETs.

Side-to-side isoperistaltic strictureplasty for chronic ischemic enteritis: Report of a case

Chronic ischemic enteritis can cause intestinal strictures, but extensive resection of the small intestine may leave patients with short bowel syndrome. Thus, the importance of preserving diseased small bowel is now recognized. We report a case of successful side-to-side isoperistaltic strictureplasty (SSIS), performed to prevent short bowel syndrome, in a patient with ischemic enteritis caused by strangulated intestinal obstruction. SSIS is useful for preserving the intestinal absorptive function in patients with a long narrowed bowel loop caused by ischemic change. To our knowledge, this is the first report of the successful treatment of a long stricture resulting from ischemic enteritis, achieved by performing SSIS.

Neuroendocrine tumor of the pancreas with rhabdoid feature

Imaging of a 53-year-old Japanese man revealed two tumors in the liver and a tumor in the head of the pancreas with a swelling lymph node. A needle biopsy for the liver tumors was performed, revealing a neuroendocrine tumor. Enucleation, lymphadenectomy, and partial hepatectomy were performed. The microscopic examination identified many tumor cells with intracytoplasmic inclusions arranged in a nested, cord, or tubular fashion. The intracytoplasmic inclusions displayed densely eosinophilic globules and displaced the nuclei toward the periphery, which constitutes “rhabdoid” features. The tumor cells were positive for synaptophysin and weakly positive for NCAM, but negative for chromogranin A. Epithelial markers (AE1/AE3 and CAM5.2) accentuated intracytoplasmic globules. Pancreatic neuroendocrine tumors with rhabdoid features are very rare. Generally, rhabdoid features are aggressive and dedifferentiated characteristics of various types of tumor. Pancreatic neuroendocrine tumors containing rhabdoid cells tend to display extrapancreatic spread at the time of presentation, although some of these tumors with rhabdoid features are not always associated with aggressive behavior.

SLC2A1/GLUT1 expression in mural nodules of intraductal papillary mucinous neoplasm of the pancreas

In intraductal papillary mucinous neoplasms (IPMNs), the presence of a mural nodule showing a papillary or nodular proliferation of tumor cells in the dilated pancreatic duct is an indication for resection of IPMN. Solute carrier family 2, facilitated glucose transporter member 1, known as glucose transporter type 1 (SLC2A1/GLUT1) mediates cellular glucose uptake in many carcinomas and is correlated with increased 18F-fluorodeoxyglucose (18F-FDG) uptake. We examined SLC2A1/GLUT1 expression in the mural nodules of 180 IPMN specimens to distinguish malignant/benign tumors. A mural nodule was detected in 80 (44.4%) of the IPMNs, and was detected in 18.6% (13/70) of the IPMN-low (dysplasia) specimens, 36.1% (13/36) of the IPMN-int, 93.3% (28/30) of the IPMN-high, and 59.1% (26/44) of the IPMN-inv (with an associated invasive carcinoma) specimens. The sensitivity for detecting mural nodules was 81.7% by endoscopic ultrasonography, 70% by contrast-enhanced computed tomography and 54% by endoscopic retrograde cholangiopancreatography. SLC2A1/GLUT1 expression in the mural nodules was recognized in the basal and basolateral cytomembrane of tumor cells and was expressed in 15.4% (2/13) of the IPMN-low, 15.4% (2/13) of the IPMN-int, 71.4% (20/28) of the IPMN-high and 84.6% (22/26) of the IPMN-inv groups. The SLC2A1/GLUT1 expression was significantly higher in the IPMN-high and IPMN-inv mural nodules than in those of the IPMN-low and IPMN-int groups. Our findings suggest that SLC2A1/GLUT1 is expressed late in the adenoma-carcinoma sequence during carcinogenesis in IPMN, and SLC2A1/GLUT1 act as therapeutic target for malignant IPMN.