Randomized controlled study of gemcitabine plus S-1 combination chemotherapy versus gemcitabine for unresectable pancreatic cancer.

PURPOSE: The aim of this study was to evaluate efficacy and safety of gemcitabine plus S-1 (GS) combination chemotherapy in patients with unresectable pancreatic cancer. METHODS: Patients were randomly assigned to receive GS (oral S-1 60 mg/m(2) daily on days 1-15 every 3 weeks and gemcitabine 1,000 mg/m(2) on days 8 and 15) or gemcitabine (1,000 mg/m(2) on days 1, 8, and 15 every 4 weeks). The primary endpoint was progression-free survival (PFS). RESULTS: One hundred and one patients were randomly assigned. PFS was significantly longer in the GS arm with an estimated hazard ratio (HR) of 0.65 (95 % CI 0.43-0.98; P = 0.039; median 5.3 vs 3.8 months). Objective response rate (ORR) was also better in the GS arm (21.6 vs 6 %, P = 0.048). Median survival was 8.6 months for GS and 8.6 months for GEM (HR 0.93; 95 % CI 0.61-1.41; P = 0.714). Grade 3-4 neutropenia (44 vs 19.6 %, P = 0.011) and thrombocytopenia (26 vs 8.7 %, P = 0.051) were more frequent in the GS arm. CONCLUSIONS: GS therapy improved PFS and ORR with acceptable toxicity profile in patients with unresectable pancreatic cancer.

Factors affecting the accuracy of endoscopic transpapillary sampling methods for bile duct cancer.

BACKGROUND AND AIM: Various methods for endoscopic transpapillary sampling have been developed. However, the factors affecting the accuracy of these methods for bile duct cancer are unknown. The aim of the present study was to determine the factors affecting the accuracy of endoscopic transpapillary sampling methods. METHODS: We reviewed the results from 101 patients with bile duct cancer who underwent transpapillary sampling by aspiration bile cytology, brushing cytology, and fluoroscopic forceps biopsy. The final diagnosis of bile duct cancer was made on the basis of pathological evaluation of specimens obtained at surgery and the clinical course over at least 1 year in patients not operated on. We carried out subgroup analyses for the factors affecting the accuracy of each transpapillary sampling method. RESULTS: Aspiration bile cytology was carried out 238 times in 77 patients, brushing cytology was carried out 67 times in 60patients, and fluoroscopic forceps biopsy was carried out 64 times in 53 patients. Accuracies of aspiration bile cytology were significantly higher for longer (≥15 mm) biliary cancerous lesions than for shorter (<15 mm) lesions (30% vs 18%, respectively, P = 0.049). Accuracies of brushing cytology and fluoroscopic forceps biopsy were significantly higher for non-flat than for flat-type biliary cancerous lesions (brushing: 58% vs 38%, respectively, P = 0.032; forceps biopsy: 60% vs 33%, respectively, P = 0.043). CONCLUSION: Endoscopic transpapillary sampling methods are more accurate for longer or elevated (non-flat) biliary cancerous lesions than for shorter or flat lesions.

Hypertonic saline-epinephrine local injection therapy for post-endoscopic sphincterotomy bleeding: removal of blood clots using pure ethanol local injection.

PURPOSE: Bleeding following endoscopic sphincterotomy (EST) is a rare but unavoidable complication of the procedure. We routinely perform local injection of hypertonic saline-epinephrine (HSE) for the treatment of post-EST bleeding. Any blood clot is removed only by irrigation with water after local injection of pure ethanol into the blood clot to cause crusting. We evaluated the usefulness of this treatment method. METHODS: Subjects were 8 patients (1.2%) with post-EST bleeding requiring hemostatic intervention among 682 patients undergoing EST. After determination of the bleeding point, local injection of HSE was performed. When an adherent blood clot was present, pure ethanol was injected into the blood clot and then irrigation with water was performed to remove the blood clot. RESULTS: Endoscopic hemostasis was successfully achieved in all the 8 patients (100%). In 4 patients (50%), the adherent blood clots were successfully removed only with pure ethanol local injection into the blood clot followed by irrigation with water. No complications of the hemostatic procedure occurred in any patients. CONCLUSIONS: This study indicated that hemostasis with HSE local injection can be safe and useful for the treatment of post-EST bleeding, and also that blood clot removal with pure ethanol local injection can be useful.

Metformin, a diabetes drug, eliminates tumor-initiating hepatocellular carcinoma cells.

Metformin has been widely used as an oral drug for diabetes mellitus for approximately 60 years. Interestingly, recent reports showed that metformin exhibited an anti-tumor action in a wide range of malignancies including hepatocellular carcinoma (HCC). In the present study, we investigated its impact on tumor-initiating HCC cells. Metformin suppressed cell growth and induced apoptosis in a dose-dependent manner. Flow cytometric analysis showed that metformin treatment markedly reduced the number of tumor-initiating epithelial cell adhesion molecule (EpCAM)(+) HCC cells. Non-adherent sphere formation assays of EpCAM(+) cells showed that metformin impaired not only their sphere-forming ability, but also their self-renewal capability. Consistent with this, immunostaining of spheres revealed that metformin significantly decreased the number of component cells positive for hepatic stem cell markers such as EpCAM and α-fetoprotein. In a xenograft transplantation model using non-obese diabetic/severe combined immunodeficient mice, metformin and/or sorafenib treatment suppressed the growth of tumors derived from transplanted HCC cells. Notably, the administration of metformin but not sorafenib decreased the number of EpCAM(+) cells and impaired their self-renewal capability. As reported, metformin activated AMP-activated protein kinase (AMPK) through phosphorylation; however its inhibitory effect on the mammalian target of rapamycin (mTOR) pathway did not necessarily correlate with its anti-tumor activity toward EpCAM(+) tumor-initiating HCC cells. These results indicate that metformin is a promising therapeutic agent for the elimination of tumor-initiating HCC cells and suggest as-yet-unknown functions other than its inhibitory effect on the AMPK/mTOR pathway.

Erlotinib prolongs survival in pancreatic cancer by blocking gemcitabine-induced MAPK signals.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most deadly cancers worldwide. Although many regimens have been used for PDAC treatment, the combination of the EGF receptor (EGFR) inhibitor erlotinib with gemcitabine has been the only molecular-targeted drug tested so far that has been superior to gemcitabine alone. The mechanism underlying this effective combinational regimen remains unknown. Here, we show that the combination is superior to gemcitabine alone in blocking progression and prolonging survival in a murine model of PDAC (Kras activation with Tgfbr2 knockout). We found that gemcitabine induced mitogen-activated protein kinase signaling, which was dramatically inhibited by erlotinib even in the Kras-activated PDAC cells in the mouse model. Mechanistic investigations suggested that gemcitabine induces EGFR ligand expression and ERBB2 activation by increasing heterodimer formation with EGFR, thereby maintaining high levels of ERBB2 protein in PDAC cells. Overall, our findings suggest a significant role of ERBB in PDAC treatment.

Endoscopic sphincterotomy combined with large balloon dilation for removal of large bile duct stones.

BACKGROUND/AIMS: Recently, there have been sporadic reports of lithotomy using endoscopic sphincterotomy combined with large balloon dilation (EPLBD) against large or multiple bile duct stones. However, there are not many reports so far concerning this procedure. Therefore, we decided to discuss the results of EPLBD against large or multiple bile duct stones. METHODOLOGY: Stone retrieval using EPLBD was performed with 59 patients of choledocholithiasis, A) with 13 mm or more in shortest dimension, or B) multiple (≥3) bile duct stones, with the smallest more than 10 mm in shortest dimension. The papilla treated with endoscopic sphincterotomy (EST) was dilated using a 12-20 mm balloon suitable for the biliary ductal size. RESULTS: The success rate for the first lithotomy for choledocholithiasis was 83.1% (49/59). The final lithotomy rate was 100% (59/59). The time required for lithotomy was 43.7 (12-125) minutes and the number of treatment was 1.3 (1-4) on average. Lithotripsy was needed in 13.6% (8/59). The incidence of coincidental events associated with the procedure was 6.8% (4/59). No pancreatitis was noted. CONCLUSIONS: An endoscopic treatment using EST plus large balloon dilation against large or multiple bile duct stones was suggested to be safe and effective.

Clinical usefulness of repeated pancreatic juice cytology via endoscopic naso-pancreatic drainage tube in patients with pancreatic cancer.

BACKGROUND: Cytological examination of pancreatic juice obtained during endoscopic retrograde cholangiopancreatography (ERCP) is well established, but its sensitivity for pancreatic cancer has not been satisfactory. The aim of this study was to evaluate the usefulness of repeated pancreatic juice cytology (PJC) via the endoscopic naso-pancreatic drainage (ENPD) tube in patients with pancreatic cancer compared with conventional PJC. METHODS: We retrospectively investigated 139 patients with pancreatic disease. Between April 2004 and November 2007, conventional PJC was performed in 56 patients with pancreatic cancer and 23 with benign pancreatic stricture. Between January 2008 and November 2010, ENPD was used in 40 patients with pancreatic cancer and 20 with benign pancreatic stricture. The ENPD tube was placed into the main pancreatic duct for up to 3 days, and cytological samples of pancreatic juice were collected up to 6 times in total. RESULTS: Sensitivity, specificity, positive predictive value, negative predictive value, and overall accuracy of the ENPD method for pancreatic cancer were 80, 100, 100, 71, and 87 %, respectively, revealing significantly higher sensitivity than the conventional method (p = 0.0001). Sensitivities according to tumor location and size were 90 % (19/21), 69 % (9/13), and 67 % (4/6) in the head, body, and tail of the pancreas, 88 % (7/8), 79 % (19/24), and 75 % (6/8) in tumors with a diameter less than 20 mm including carcinoma in situ, 21-40, and greater than 41 mm, respectively. CONCLUSIONS: The ENPD method was found to have high diagnostic yield, especially for tumors less than 20 mm or located in the pancreatic head, and might be useful for the diagnosis of early-stage pancreatic cancer.

Use of F-18 fluorodeoxyglucose positron emission tomography with dual-phase imaging to identify intraductal papillary mucinous neoplasm.

BACKGROUND & AIMS: We investigated the usefulness of dual-phase F-18 fluorodeoxyglucose positron emission tomography with computed tomography (FDG-PET/CT) to differentiate benign from malignant intraductal papillary mucinous neoplasms (IPMNs) and to evaluate branch-duct IPMNs. METHODS: We used FDG-PET/CT to evaluate IPMNs in 48 consecutive patients who underwent surgical resection from May 2004 to March 2012. IPMNs were classified as benign (n = 16) or malignant (n = 32) on the basis of histology analysis. The ability of FDG-PET/CT to identify branch-duct IPMNs was compared with that of the International Consensus Guidelines. RESULTS: The maximum standardized uptake value (SUVmax) was higher for early-phase malignant IPMNs than that for benign IPMNs (3.5 ± 2.2 vs 1.5 ± 0.4, P < .001). When the SUVmax cutoff value was set at 2.0, early-phase malignant IPMNs were identified with 88% sensitivity, specificity, and accuracy. The retention index values for malignant and benign IPMNs were 19.6 ± 17.8 and -2.6 ± 12.9, respectively. When the SUVmax cutoff was set to 2.0 and the retention index value to -10.0, early-phase malignant IPMNs were identified with 88% sensitivity, 94% specificity, and 90% accuracy. In identification of branch-duct IPMNs, when the SUVmax cutoff was set to 2.0, the sensitivity, specificity, and accuracy values were 79%, 92%, and 84%, respectively. By using a maximum main pancreatic duct diameter ≥7 mm, the Guidelines identified branch-duct IPMNs with greater specificity than FDG-PET/CT. The Guidelines criteria of maximum cyst size ≥30 mm and the presence of intramural nodules identified branch-duct IPMNs with almost equal sensitivity to FDG-PET/CT. CONCLUSIONS: Dual-phase FDG-PET/CT is useful for preoperative identification of malignant IPMN and for evaluating branch-duct IPMN.

Aldehyde dehydrogenase 1 is associated with recurrence-free survival but not stem cell-like properties in hepatocellular carcinoma.

AIM: It has been reported that aldehyde dehydrogenase 1 A1 (ALDH1) could be not only a normal stem cell marker but also a cancer stem cell marker. ALDH1 expression could be a predictor of poor prognosis in a wide range of cancers. However, the role of ALDH1 in hepatocellular carcinoma (HCC) remains unclear. METHOD: We conducted loss-of-function assays for ALDH1 by using short-hairpin RNA in HCC cells and evaluated the correlation between ALDH1 expression and clinicopathological features based on immunohistochemical assessment of 49 primary HCC tissues. RESULTS: Neither cell proliferation nor the anchorage-independent sphere formation ability of HCC cells were altered after ALDH1 knockdown. Flow cytometric analyses revealed that ALDH1 knockdown showed no remarkable change in the proportion of epithelial cell adhesion molecule (EpCAM)(+) tumor-initiating cells. Although non-tumor tissues in primary HCC samples diffusely and homogenously expressed ALDH1 at low levels, tumor tissues contained cells with high levels of ALDH1 expression at varying frequencies. Primary HCC samples were categorized as ALDH1-high or ALDH1-low based on the percentage of ALDH1-overexpressing cells. ALDH1-high HCC was characterized by low serum levels of α-fetoprotein (P < 0.01) and well-differentiated pathology (P = 0.03). Multivariate analysis showed that high ALDH1 expression was a favorable prognostic factor in recurrence-free survival of HCC (P = 0.02). CONCLUSION: Our findings show that ALDH1 expression has little association with stem cell-like features in HCC cells. ALDH1 might function as a differentiation marker rather than a stem cell marker in HCC.

Current situation of endoscopic treatment for common bile duct stones.

BACKGROUND/AIMS: The progression of endoscopy and devices as well as newly developed treatment methods have enabled endoscopic lithotomy. In this study, we examined to what degree is it possible to endoscopically treat patients who are diagnosed as having common bile duct stones. METHODOLOGY: Lithotomy was conducted using a backward side-viewing endoscope for patients without surgical history of upper gastrointestinal tract and patients with stomach reconstructed with Billroth-I method, using an ordinary endoscope for patients with stomach reconstructed with Billroth-II method (Bil-II) and using a double balloon endoscope for patients with difficulty in reaching the papilla or patients of Roux-en-Y anastomosis (R-Y). As for treatment methods, we selected endoscopic sphincterotomy as the first choice for papilla treatment and selected endoscopic papillary balloon dilation for patients with bleeding tendency or patients of Bil-II or R-Y. For patients with multiple stones or giant stones, lithotripsy was selected depending on judgment of the endoscopist. RESULTS: Endoscopic complete lithotomy was successful in 97.7% (168/172). An accidental disease was observed in 2.9% (5/172). In one patient with the perforated gastrointestinal tract, a surgery was performed but others were mild. CONCLUSIONS: Common bile duct stones can be endoscopically treated safely with high rate.

3-Deazaneplanocin A is a promising therapeutic agent for the eradication of tumor-initiating hepatocellular carcinoma cells.

Recent advances in stem cell biology have identified tumor-initiating cells (TICs) in a variety of cancers including hepatocellular carcinoma (HCC). Polycomb group gene products such as BMI1 and EZH2 have been characterized as general self-renewal regulators in a wide range of normal stem cells and TICs. We previously reported that Ezh2 tightly regulates the self-renewal and differentiation of murine hepatic stem/progenitor cells. However, the role of EZH2 in tumor-initiating HCC cells remains unclear. In this study, we conducted loss-of-function assay of EZH2 using short-hairpin RNA and pharmacological inhibition of EZH2 by an S-adenosylhomocysteine hydrolase inhibitor, 3-deazaneplanocin A (DZNep). Both EZH2-knockdown and DZNep treatment impaired cell growth and anchorage-independent sphere formation of HCC cells in culture. Flow cytometric analyses revealed that the two approaches decreased the number of epithelial cell adhesion molecule (EpCAM)(+) tumor-initiating cells. Administration of 5-fluorouracil (5-FU) or DZNep suppressed the tumors by implanted HCC cells in non-obese diabetic/severe combined immunodeficient mice. Of note, however, DZNep but not 5-FU predominantly reduced the number of EpCAM(+) cells and diminished the self-renewal capability of these cells as judged by sphere formation assays. Our findings reveal that tumor-initiating HCC cells are highly dependent on EZH2 for their tumorigenic activity. Although further analyses of TICs from primary HCC would be necessary, pharmacological interference with EZH2 might be a promising therapeutic approach to targeting tumor-initiating HCC cells.

Different subtypes of intraductal papillary mucinous neoplasm in the pancreas have distinct pathways to pancreatic cancer progression.

BACKGROUND: Intraductal papillary mucinous neoplasm (IPMN) is recognized as a precursor lesion to pancreatic cancer, a unique pathological entity. IPMN has subtypes with different clinical characteristics. However, the molecular mechanisms of cancer progression from IPMN remain largely unknown. In this study we examined the differences in genetic alteration(s) among the IPMN subtypes. METHODS: Surgically resected IPMNs (n = 25) were classified into four subtypes by hematoxylin and eosin (H&E) and mucin immunostaining. Mutations in KRAS, BRAF, and PIK3CA genes and expression of CDKN2A, TP53, SMAD4, phospho-ERK, and phospho-SMAD1/5/8 proteins were examined. RESULTS: There were 11 gastric, 11 intestinal, one pancreatobiliary, and two oncocytic types in this study. We then compared the two major subtypes, gastric-type and intestinal-type IPMN. Gastric-type IPMN showed a significantly higher incidence of KRAS mutations (9/11, 81.8%) compared with intestinal type (3/11, 27.3%; p < 0.05), although the intestinal type showed a higher grade of dysplasia than gastric type (p < 0.01). All cases with KRAS mutations showed phospho-ERK immunostaining. In contrast, intestinal type (9/11, 81.8%) showed more frequent SMAD1/5/8 phosphorylation compared with gastric-type IPMN (3/11, 27.3%; p < 0.05%). CONCLUSIONS: There may be distinct mechanisms of pancreatic cancer progression in the different subtypes of IPMN. In particular, KRAS mutation and bone morphogenetic protein-SMAD signaling status may be crucial diverging steps for the two representative pathways to pancreatic cancer in IPMN patients.

New cannulation method for pancreatic duct cannulation-bile duct guidewire-indwelling method.

The patient was a 58-year-old male with symptomatic alcoholic chronic pancreatitis. Since a 10 mm calculus was observed in the pancreatic body and abdominal pain occurred due to congestion of pancreatic juice, endoscopic retrograde cholangiopancreatography was conducted for assessment of the pancreatic duct and treatment of pancreatic calculus. Pancreatogram was slightly and insufficiently obtained by injecting the contrast media via the common channel of the duodenal main papilla. We tried to cannulate selectively into the pancreatic duct for a clear image. However, the selective cannulation of the pancreatic duct was difficult because of instability of the papilla. On the other hand, selective cannulation of the bile duct was relatively easily achieved. Therefore, after the imaging of the bile duct, a guidewire was retained in the bile duct to immobilize the duodenal papilla and cannulation of the pancreatic duct was attempted. As a result, selective pancreatic duct cannulation became possible. It is considered that the bile duct guidewire-indwelling method may serve as one of the useful techniques for cases whose selective pancreatic duct cannulation is difficult ("selective pancreatic duct difficult cannulation case").

Transpancreatic precut papillotomy in patients with difficulty in selective biliary cannulation.

BACKGROUND/AIMS: Transpancreatic precut papillotomy (TPPP) is considered as an effective method in patients with difficulty in selective biliary cannulation. However, the use of placing a pancreatic duct stent as a measure against post-ERCP pancreatitis has not been clarified. Here we examine the methods of implementing TPPP safely. METHODOLOGY: TPPP was conducted on patients with difficulty in selective biliary cannulation. The incidence of pancreatitis was compared between group P(+) in which a spontaneous dislodgement type pancreatic duct stent was placed and group P(-) without a duct stent. RESULTS: The success rate of biliary cannulation was 83.3% at the first ERCP and finally 93.9%. Post-ERCP pancreatitis was observed in 9.09% of patients. The success rate of placement of pancreatic duct stent in the P(+) group was 100%. The incidence of pancreatitis in the P(+) group was 4.1% and the mean post-ERCP amylase level was 340.071 ±420.035IU/L. The incidence of pancreatitis in the P(-) group was 23.5% and the mean post-ERCP amylase level was 661.250±772.285IU/L. The incidence of pancreatitis and the mean post-ERCP amylase level were significantly lower in the P(+) group (p<0.05). CONCLUSIONS: In the patients with difficulty in selective biliary cannulation, TPPP is a useful technique for biliary cannulation. The placement of a spontaneous dislodgement type pancreatic duct stent after TPPP may be useful for prevention of post-ERCP pancreatitis.

Inhibiting Cxcr2 disrupts tumor-stromal interactions and improves survival in a mouse model of pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC), one of the most lethal neoplasms, is characterized by an expanded stroma with marked fibrosis (desmoplasia). We previously generated pancreas epithelium-specific TGF-ß receptor type II (Tgfbr2) knockout mice in the context of Kras activation (mice referred to herein as Kras+Tgfbr2KO mice) and found that they developed aggressive PDAC that recapitulated the histological manifestations of the human disease. The mouse PDAC tissue showed strong expression of connective tissue growth factor (Ctgf), a profibrotic and tumor-promoting factor, especially in the tumor-stromal border area, suggesting an active tumor-stromal interaction. Here we show that the PDAC cells in Kras+Tgfbr2KO mice secreted much higher levels of several Cxc chemokines compared with mouse pancreatic intraepithelial neoplasia cells, which are preinvasive. The Cxc chemokines induced Ctgf expression in the pancreatic stromal fibroblasts, not in the PDAC cells themselves. Subcutaneous grafting studies revealed that the fibroblasts enhanced growth of PDAC cell allografts, which was attenuated by Cxcr2 inhibition. Moreover, treating the Kras+Tgfbr2KO mice with the CXCR2 inhibitor reduced tumor progression. The decreased tumor progression correlated with reduced Ctgf expression and angiogenesis and increased overall survival. Taken together, our data indicate that tumor-stromal interactions via a Cxcr2-dependent chemokine and Ctgf axis can regulate PDAC progression. Further, our results suggest that inhibiting tumor-stromal interactions might be a promising therapeutic strategy for PDAC.

Utility of placement of pancreatic duct spontaneous dislodgement stent for prevention of post-ERCP pancreatitis in patients with difficulty in selective biliary cannulation.

BACKGROUND/AIMS: To examine the utility of placement of pancreatic duct spontaneous dislodgement stents for prevention of post-ERCP pancreatitis in patients with difficulty in selective biliary cannulation. METHODOLOGY: The incidence of pancreatitis was compared between the group with P(+) pancreatic duct spontaneous dislodgement stent placed for prevention of post-ERCP pancreatitis and the group without P(-) in patients with difficulty in selective biliary cannulation. RESULTS: The final success rate of selective biliary cannulation was 94.45%. Post-ERCP pancreatitis was observed at 7.07%. The success rate of placement of pancreatic duct stent in the P(+) group was 99.0%. The incidence of pancreatitis in 99 patients in the P(+) group was 3.0%, that of abdominal pain was 3.0%, that of hyperamylasemia was 16.2%, and the mean post-ERCP amylase level was 353.031 +/- 520.792 IU/L. The incidence of pancreatitis in the P(-) group was 11.1%, that of abdominal pain was 20.2%, that of hyperamylasemia was 33.3%, and the mean post-ERCP amylase level was 541.204 +/- 771.843 IU/L. Comparing between the P(+) group and P(-) group, the incidence of pancreatitis, that of abdominal pain, that of hyperamylasemia and the mean post-ERCP amylase level were significantly decreased in the P(+) group (p<0.05). CONCLUSION: Placement of pancreatic duct spontaneous dislodgement stent in patients with difficulty in selective biliary cannulation could be useful for prevention of post-ERCP pancreatitis.

Pancreatic duct guidewire-indwelling method for patients resistant to selective biliary cannulation and usefulness of pre-cut papillotomy following unsuccessful biliary cannulation with pancreatic duct guidewire-indwelling method.

BACKGROUND/AIMS: Pancreatic duct guidewire-indwelling method (P-GW) is effective when selective biliary cannulation (SBC) has failed, but neither its true success rate nor a salvage technique have been established. In this study, we examined the usefulness of pre-cut papillotomy employing a pancreatic duct guidewire as the salvage treatment after unsuccessful SBC under P-GW. METHODOLOGY: P-GW was conducted in 55 patients. When cannulation under P-GW was unsuccessful, pre-cut papillotomy was performed. Then, if SBC after trial was still unsuccessful, ERCP was tried again at a later date. The incidence of pancreatitis following ERCP in patients with difficult SBC, with and without pancreatic duct stenting was determined. RESULTS: P-GW resulted in successful SBC in 63.6% of patients. For the 20 patients in which SBC failed pre-cut papillotomy using the pancreatic duct guidewire was performed. Transpancreatic pre-cut papillotomy was performed in 17 patients; 3 patients underwent needle-knife pre-cut papillotomy. SBC was successful at first attempt in 89.1% and eventually in 96.4% of patients. Post-ERCP pancreatitis occurred in 7.3%, broken down into 0% for those with pancreatic duct stenting (p=0.03) and 16.7% for those without. CONCLUSIONS: Pre-cut papillotomy using a pancreatic duct guidewire was useful for patients with unsuccessful SBC with P-GW alone, and the risk for pancreatitis was reduced by pancreatic stenting.

Altered composition of fatty acids exacerbates hepatotumorigenesis during activation of the phosphatidylinositol 3-kinase pathway.

BACKGROUND & AIMS: Some clinical findings have suggested that systemic metabolic disorders accelerate in vivo tumor progression. Deregulation of the phosphatidylinositol 3-kinase (PI3K)/Akt pathway is implicated in both metabolic dysfunction and carcinogenesis in humans; however, it remains unknown whether the altered metabolic status caused by abnormal activation of the pathway is linked to the protumorigenic effect. METHODS: We established hepatocyte-specific Pik3ca transgenic (Tg) mice harboring N1068fs*4 mutation. RESULTS: The Tg mice exhibited hepatic steatosis and tumor development. PPARγ-dependent lipogenesis was accelerated in the Tg liver, and the abnormal profile of accumulated fatty acid (FA) composition was observed in the tumors of Tg livers. In addition, the Akt/mTOR pathway was highly activated in the tumors, and in turn, the expression of tumor suppressor genes including Pten, Xpo4, and Dlc1 decreased. Interestingly, we found that the suppression of those genes and the enhanced in vitro colony formation were induced in the immortalized hepatocytes by the treatment with oleic acid (OA), which is one of the FAs that accumulated in tumors. CONCLUSIONS: Our data suggest that the unusual FA accumulation has a possible role in promoting in vivo hepato-tumorigenesis under constitutive activation of the PI3K pathway. The Pik3ca Tg mice might help to elucidate molecular mechanisms by which metabolic dysfunction contributes to in vivo tumor progression.

Reduced expression of RAS protein activator like-1 in gastric cancer.

RAS signaling is frequently deregulated in human neoplasms. However, RAS mutations have been found in only a small proportion of human gastric cancers, implicating other mechanisms in the activation of RAS signaling in gastric tumorigenesis. We have previously reported that decreased expression of RAS protein activator like-1 (RASAL1), a member of the RAS-GTPase-activating proteins that switch off RAS activity, contributes to colon tumor progression. In our study, we explored the involvement of decreased RASAL1 expression in gastric tumorigenesis. RASAL1 expression was reduced in 6 of 10 gastric cancer cell lines examined by immunoblotting. Knockdown of RASAL1 increased mitogen-activated protein kinase signaling in response to growth factor stimulation, and the forced expression of RASAL1 reduced proliferation of gastric cancer cells. Immunohistochemical analyses in primary gastric tumors showed that RASAL1 expression was reduced in 23 of 48 (48%) of the gastric cancers but in none of the adenomas (0/10). Methylation of the RASAL1 promoter region and loss of heterozygosity (LOH) at the RASAL1 locus were examined to investigate the causes of RASAL1 silencing. All cell lines with reduced RASAL1 had RASAL1 methylation, and two had LOH. In primary gastric cancers, methylation or LOH was detected in 50% (6/12) of those with reduced RASAL1. Furthermore, RASAL1 expression was restored in some cell lines by histone deacetylase inhibitor treatment. Our findings demonstrate that reduced RASAL1 expression, partly due to genetic and epigenetic changes, contributes to gastric carcinogenesis, and also re-emphasize the importance of RAS signaling in gastric cancer development.