Tsutomu Izawa

Gemcitabine chemoresistance and molecular markers associated with gemcitabine transport and metabolism in human pancreatic cancer cells

To identify predictive molecular markers for gemcitabine resistance, we investigated changes in the expression of four genes associated with gemcitabine transport and metabolism during the development of acquired gemcitabine resistance of pancreatic cancer cell lines. The expression levels of human equilibrative nucleoside transporter-1 (hENT1), deoxycytidine kinase (dCK), RRM1, and RRM2 mRNA were analysed by real-time light cycler-PCR in various subclones during the development of acquired resistance to gemcitabine. Real-time light cycler-PCR demonstrated that the expression levels of either RRM1 or RRM2 progressively increased during the development of gemcitabine resistance. Expression of dCK was slightly increased in cells resistant to lower concentrations of gemcitabine, but was decreased below the undetectable level in higher concentration-resistant subclones. Expression of hENT1 was increased in the development of gemcitabine resistance. As acquired resistance to gemcitabine seems to correlate with the balance of these four factors, we calculated the ratio of hENT1 × dCK/RRM1 × RRM2 gene expression in gemcitabine-resistant subclones. The ratio of gene expression decreased progressively with development of acquired resistance in gemcitabine-resistant subclones. Furthermore, the expression ratio significantly correlated with gemcitabine sensitivity in eight pancreatic cancer cell lines, whereas no single gene expression level correlated with the sensitivity. These results suggest that the sensitivity of pancreatic cancer cells to gemcitabine is determined by the ratio of four factors involved in gemcitabine transport and metabolism. The ratio of the four gene expression levels correlates with acquired gemcitabine-resistance in pancreatic cancer cells, and may be useful as a predictive marker for the efficacy of gemcitabine therapy in pancreatic cancer patients.

Clonality and field cancerization in intraductal papillary-mucinous tumors of the pancreas

Multiple lesions of intraductal papillary‐mucinous tumor of the pancreas (IPMT) in the same pancreas often are encountered. To elucidate field (multicentric) cancerization and clonality of IPMT, clonal analyses of IPMT and its precursor lesion of ductal hyperplasia were performed. K‐ras codon 12 mutations and X‐chromosome inactivation of human androgen receptor gene (HUMARA) were investigated.

Solitary true cyst of the pancreas in two adults: analysis of cyst fluid and review of the literature

Solitary true cyst of the pancreas in adults is extremely rare. We report two adult cases of solitary true cyst of the pancreas. In a 53-yr-old woman there was discovered, incidentally, a unilocular cyst of 7.0 × 6.5 cm in size in the tail of the pancreas that was noted on abdominal US and CT scan. A 16-yr-old boy presented with abdominal pain, and an abdominal US and CT scan revealed a 6.5 cm cystic mass located in the tail of the pancreas. Both patients underwent distal pancreatectomy. Histologically, the cyst was lined with flattened cuboidal and squamous epithelium without morphological alterations. Analysis of the cyst fluid revealed high CA 19-9 (>100,000 U/L) and Span-1 levels (>60,000 U/L) in both cases. Immunohistochemically, the lining epithelial cells of true cyst were positive for CA 19-9 staining. The clinicopathological features of solitary true cyst of the pancreas in adults are briefly reviewed.

α-Fetoprotein-producing adenocarcinoma of the pancreas presenting focal hepatoid differentiation

SummaryWe report a rare case of pancreatic carcinoma producing α-fetoprotein (AFP), showing focal hepatoid differentiation in metastatic lymph nodes. A 65-yr-old female was admitted because of abdominal pain. The serum AFP was measured at 16,170 ng/mL. Radiological examinations revealed a mass measuring 6 cm in diameter in the body and tail of the pancreas. A right supraclavicular lymphadenopathy was found and biopsied. Light microscopy showed a tumor consisting of a portion of a hepatoid area and well-differentiated adenocarcinoma, which was suggestive of a hepatoid adenocarcinoma. Immunohistochemical analysis showed that the tumor cells expressed AFP, α1-antitrypsin (AT) and albumin. Although the pathological diagnosis of the primary pancreatic tumor was not obtained, this appears to be the first case of hepatoid adenocarcinoma of the pancreas.

Pancreatic duct obstruction caused by malignant islet cell tumors of the pancreas.

Islet cell tumors of the pancreas represent 1% to 2% of all pancreatic tumors.1 Although diagnosis is highly accurate with imaging modalities such as CT and EUS,2-4 it is difficult to differentiate preoperatively between malignant and benign variants unless metastases and/or invasion of adjacent organs are present.5-7 ERCP continues to play a major role in the diagnosis of pancreatic diseases despite recent advances in and the widespread use of noninvasive diagnostic imaging modalities. There is, however, limited information available about the pancreatograms of islet cell tumors including findings that suggest whether the tumor is benign or malignant.7 Partial obstruction (stenosis) and complete obstruction of the main pancreatic duct are common findings that suggest pancreatic cancer; these occur in most cases of pancreatic malignancy but are unusual with islet cell tumors.8,9 If available, a clinical imaging finding highly suggestive of malignancy of islet cell tumor would be important in the preoperative assessment of patients without apparent metastasis. We encountered 2 cases of malignant islet cell tumors in which complete obstruction of the main pancreatic duct was demonstrated by ERCP.

Proliferative potential and K-ras mutation in epithelial hyperplasia of the gallbladder in patients with anomalous pancreaticobiliary ductal union

BACKGROUND Recent studies have shown that anomalous pancreaticobiliary ductal union (APBD) is an important risk factor for the development of gallbladder carcinoma. Epithelial hyperplasia of the gallbladder is one of the characteristic changes, but it is not clear whether epithelial hyperplasia is a premalignant lesion that could lead to cancer in APBD patients. METHODS Twenty-four APBD patients were classified into two types: patients with bile duct dilation (dilated type) (n 13) and patients without dilation (undilated type) (n = 11). Resected gallbladders obtained from APBD patients and control patients without APBD were examined histologically and with immunohistochemical techniques for the detection of p53 and Ki-67 (as a cell proliferation marker). K-ras mutations were examined using polymerase chain reaction-restriction fragment length polymorphism and direct DNA sequence analysis. The patients were also classified, according to extent of epithelial hyperplasia, as having high grade or low grade hyperplasia. RESULTS Fifteen (63%) of 24 APBD patients had epithelial hyperplasia of the gallbladder, whereas no patients without APBD exhibited this lesion. The incidence of epithelial hyperplasia was significantly higher in the gallbladders of undilated-type APBD patients (91%) than in those of dilated-type patients (38%) (P < 0.01). Three of 24 APBD patients (13%) had gallbladder carcinoma, and 2 of the 3 gallbladder carcinomas (67%) were accompanied by diffuse epithelial hyperplasia of the gallbladder. Among 21 nonneoplastic gallbladders, diffuse epithelial hyperplasia was observed in all (100%) of the undilated-type APBD and in 4 (33%) of 12 dilated-type APBD (P < 0.001). High grade hyperplasia was observed in 7 of 11 patients (64%) with undilated-type APBD and 2 of 13 patients (15%) with dilated-type APBD (P < 0.05). The incidence of high grade hyperplasia increased with age among patients older than 35 years. Ki-67 labeling index (LI) was significantly higher in hyperplastic mucosa than in control gallbladder mucosa. High grade hyperplasia had a significantly higher Ki-67 LI than low grade hyperplasia (P < 0.001). Two (22%) of 9 high grade hyperplasia cases had K-ras mutations, whereas none of 6 low grade hyperplasia cases had. The types of K-ras mutations in codon 12 were GTT (Val) and GAT (Asp) in each case of hyperplasia; these were identical to those of concomitant carcinomas. Neither hyperplastic nor normal mucosa exhibited p53 overexpression. CONCLUSIONS The results of this study suggest that hyperplasia of the gallbladder mucosa in APBD patients is an early change that, because of the increased proliferative activity and presence of K-ras mutations, could be considered a premalignant lesion of the gallbladder. An increased cell population of epithelial hyperplasia may predispose the mucosa to mutational events, resulting in an increased risk for the development of gallbladder carcinoma in APBD patients.

Temporary use of an accuflex stent for unextractable common bile duct stones

Endoscopic management has become the main therapeutic approach for the extraction of common bile duct (CBD) stones, and successful removal can be achieved in 80–90% patients using conventional balloon and basket techniques. However, if it is difficult to completely fragment a stone, or to clear the CBD, which may occur for a variety of reasons, the therapeutic problem will remain. When bile duct stones can not be removed, a viable management option is to place a biliary stent to ensure drainage. However, recent studies of long‐term biliary stenting, with a plastic stent, showed a relatively high rate of morbidity and mortality. We report an alternative, unique treatment for unextractable common bile duct stones, using the temporal placement of an expandable metallic stent (EMS) to facilitate passage of fragments through the papilla.

Multifocal serous cystadenoma of the pancreas. A case report and review of the literature.

SummarySerous cystadenoma of the pancreas is usually unifocal; multifocal tumors are rare. We report a case of multifocal serous cystadenoma of the pancreas in a 48-yr-old female complaining of general malaise. Serum tumor markers, such as CA 19-9, DUPAN-2, and Span-1, were elevated. Abdominal ultrasound (US) and computed tomography (CT) scans revealed two distinct cystic masses in the head and body of the pancreas, respectively. The patient underwent total pancreatectomy. The resected pancreas contained two discrete cystic masses in the head and body; no solid components were observed. Microscopically, the inner surfaces of the cysts were evenly lined by a single layer of low cuboidal or significantly attenuated epithelial cells containing clear cytoplasm and abundant glycogen without other morphological alterations. The histogenesis of serous cystadenoma is not clear; multicentric tumors may be helpful in understanding histogenesis.

A phase I study of oral uracil-tegafur prior to weekly intravenous gemcitabine in patients with advanced pancreatic cancer

Background: Gemcitabine is widely accepted as the first-line agent for advanced pancreatic cancer. The antitumor cell activity of gemcitabine is higher when administered after 5-fluorouracil (5-FU) rather than before 5-FU in an in vitro study. The present study was conducted to define the maximum tolerated dose and dose-limiting toxicity associated with an oral fluoropyrimidine prodrug that combines uracil and tegafur (UFT), given prior to weekly intravenous gemcitabine in patients with advanced pancreatic cancer. Methods: Over a 21-day cycle, gemcitabine was given intravenously over 30 min on days 8 and 15, while UFT was given orally from days 1 to 14. The dose of UFT used was 400 mg per day, given as two doses. The dose of gemcitabine was escalated in a stepwise fashion from 800 (level 1, n = 3) to 900 mg/m2 (level 2, n = 6) and then to 1,000 mg/m2 (level 3, n = 3), such that totally 12 patients received the combination chemotherapy. Results: During the first cycle, grade 3 leukopenia was observed in 2 patients at dose level 1. Only 1 patient treated at dose level 2 experienced dose-limiting toxicity (grade 3 elevated transaminase), including additional patients treated at this dose level. No grade 3/4 toxicities occurred in patients treated at dose level 3. A significant response was observed in 1 out of 12 patients (8.3%). Seven patients (58.3%) had stable disease, while 4 patients (33.3%) showed disease progression. Conclusions: The combination chemotherapy of oral UFT and gemcitabine was convenient, well tolerated and may benefit patients with advanced pancreatic cancer. Doses recommended for further study of this schedule are gemcitabine 1,000 mg/m2 and UFT 400 mg/day.

Natural History of Branch Duct Type Intraductal Papillary-Mucinous Neoplasms of the Pancreas: A Role of Endoscopic Ultrasonography in Follow-Up

Natural History of Branch Duct Type Intraductal Papillary-Mucinous Neoplasms of the Pancreas: A Role of Endoscopic Ultrasonography in Follow-Up Satoshi Tanno, Yasuhiro Nakano, Tsutomu Izawa, Yusuke Mizukami, Toshikatsu Okumura, Yutaka Kohgo Background/Aim: The aim of this study was to elucidate the natural history and serial changes of the pancreatic duct system in the patients with branch duct type intraductal papillary-mucinous neoplasms of the pancreas (IPMNs). Methods: Sixtyfive patients (forty-seven men and eighteen women) with branch duct type IPMNs were selected for follow-up and examined by endoscopic ultrasonography (EUS) two or more times (mean, 3 times). All patients who had apparent mural nodules were excluded from follow-up study. The observation periods ranged from 14 to 131 months (mean, 61 months), and all patients underwent initial endoscopic retrograde pancreatography (ERP) and computed tomography (CT). Serial changes of the pancreatic duct system, such as maximum cystic diameter and the presence of mural nodule, were studied. Results: Five (8%) of 65 patients exhibited obvious progression of cystic dilatation. New apparent mural nodules were detected in 5 cases (8%) during the observation periods. These obvious changes were observed after a 19 to 112 months follow-up period (mean, 74 months). Of five patients with mural nodules, four cases underwent surgery after follow-up study, and the pathologic diagnosis was adenoma in two and non-invasive carcinoma in two. Mural nodules were accurately diagnosed in 5 cases (100%) by EUS, whereas in one (20%) by CT and in 0 (0%) by MRCP. Five patients with cystic size enlargement were followed up without surgical resection. None of the remaining 55 patients (84%) showed increases in cystic diameter. Conclusions: Most of branch duct type IPMNs without apparent mural nodules remained unchanged. Mural nodule is an important factor affecting the follow-up. EUS is the most sensitive method to detect mural nodules in follow-up. Abstracts