Cancer-associated adipocytes promote pancreatic cancer progression through SAA1 expression.

Although pancreatic cancer often invades peripancreatic adipose tissue, little information is known about cancer-adipocyte interaction. We first investigated the ability of adipocytes to de-differentiate to cancer-associated adipocytes (CAAs) by co-culturing with pancreatic cancer cells. We then examined the effects of CAA-conditioned medium (CAA-CM) on the malignant characteristics of cancer cells, the mechanism underlying those effects, and their clinical relevance in pancreatic cancer. When 3T3-L1 adipocytes were co-cultured with pancreatic cancer cells (PANC-1) using the Transwell system, adipocytes lost their lipid droplets and changed morphologically to fibroblast-like cells (CAA). Adipocyte-specific marker mRNA levels significantly decreased but those of fibroblast-specific markers appeared, characteristic findings of CAA, as revealed by real-time PCR. When PANC-1 cells were cultured with CAA-CM, significantly higher migration/invasion capability, chemoresistance, and epithelial-mesenchymal transition (EMT) properties were observed compared with control cells. To investigate the mechanism underlying these effects, we performed microarray analysis of PANC-1 cells cultured with CAA-CM and found a 78.5-fold higher expression of SAA1 compared with control cells. When the SAA1 gene in PANC-1 cells was knocked down with SAA1 siRNA, migration/invasion capability, chemoresistance, and EMT properties were significantly attenuated compared with control cells. Immunohistochemical analysis on human pancreatic cancer tissues revealed positive SAA1 expression in 46/61 (75.4%). Overall survival in the SAA1-positive group was significantly shorter than in the SAA1-negative group (P = .013). In conclusion, we demonstrated that pancreatic cancer cells induced de-differentiation in adipocytes toward CAA, and that CAA promoted malignant characteristics of pancreatic cancer via SAA1 expression, suggesting that SAA1 is a novel therapeutic target in pancreatic cancer.

MicroRNA-296-5p Promotes Cell Invasion and Drug Resistance by Targeting Bcl2-Related Ovarian Killer, Leading to a Poor Prognosis in Pancreatic Cancer.

BACKGROUND/AIMS: Pancreatic ductal adenocarcinoma (PDAC) is characterized by aggressive invasion, early metastasis, and resistance to chemotherapy, leading to a poor prognosis. To clarify the molecular mechanism of these malignant characteristics, we performed a genome-wide microRNA (miRNA) array analysis utilizing micro-cancer tissues from patients with unresectable PDAC (stage IV), obtained by endoscopic ultrasound-fine needle aspiration (EUS-FNA). METHODS: The expression profiles of 2,042 miRNAs were determined using micro-cancer tissues from 13 patients with unresectable PDAC obtained by EUS-FNA. The relationship between individual miRNA levels and overall survival (OS) was analyzed. Possible target genes for miRNAs were bioinformatically analyzed using the online database miRDB. Pancreatic cancer cell lines PANC-1, MIA PaCa-2, and PK-8 were transfected with miRNA mimic or small interfering RNA, and cell invasion, epithelial-mesenchymal transition (EMT), and apoptosis markers were examined. miRNA and mRNA expressions were examined by quantitative polymerase chain reaction. RESULTS: Of 2,042 miRNAs, the 10 that exhibited the lowest correlation coefficient (p ≤ 0.005) between miRNA expression level and OS among the patients were identified. The miRDB and expression analysis in cancer cell lines for the 10 miRNAs identified miR-296-5p and miR-1207-5p as biomarkers predictive of shorter survival (p < 0.0005). Bioinformative target gene analysis and transfection experiments with miRNA mimics showed that Bcl2-related ovarian killer (BOK), a pro-apoptotic gene, is a target for miR296-5p in pancreatic cancer cells; transfection of miR-296-5p mimic into PANC-1, MIA PaCa-2, and PK-8 cells resulted in significant suppression of BOK mRNA and protein expression. These transfectants showed significantly higher invasion capability compared with control cells, and knock down of BOK in pancreatic cancer cells similarly enhanced invasion capability. Transfectants of miR-296-5p mimic also exhibited aberrant expression of EMT markers, including vimentin and N-cadherin. Moreover, these transfectants showed a significantly lower apoptosis rate in response to 5-fluorouracil and gemcitabine with a decrease of BOK expression, suggesting a role of miR-296-5p in drug resistance. CONCLUSION: These results suggest that miR-296-5p is a useful biomarker for a poor prognosis in patients with PDAC, and that the miR-296-5p/BOK signaling axis plays an important role in cell invasion, drug resistance, and EMT in PDACs.

Ectopic origin of bronchial arteries: still a potential pitfall in embolization.

PURPOSE: To evaluate the influence of ectopic origin of bronchial arteries (BAs) on bronchial artery embolization (BAE) for hemoptysis. METHODS: CT and angiography images of 50 consecutive sessions in 39 patients (aged 26-93 years; mean, 70.6 years) who underwent BAE for hemoptysis from April 2010 to December 2019 were reviewed. We defined ectopic BA as a systemic artery originating from other than the T5-T6 vertebral level of the descending aorta with course along the major bronchi. The background of patients, number of BAs, culprit arteries, and treatment outcomes were compared between the cases with and without ectopic BAs. RESULTS: Seventeen patients (43.6%) demonstrated 19 ectopic BAs, originating from the subclavian artery (n = 7), aortic arch above the T5-T6 level (n = 6), internal mammary artery (n = 3), brachiocephalic trunk (n = 2) or lower descending thoracic aorta (n = 1). Total number of BAs in the cases with ectopic BA was significantly greater than those in cases without ectopic BA (p = 0.0062). Required sessions of embolization were similar in the two groups. No procedure-related significant complications were noted; however, four ectopic BAs caused unexpected filling of contrast media or migration of the embolic material from the orthotopic BA to ectopic BA originating from the arch vessels via tiny communication. CONCLUSION: Although BAE under the presence of ectopic BA is feasible and safe, detection of BAs with ectopic origin, even of small diameter, is needed to avoid risk of non-target coursing of embolic materials.

Downregulation of microRNA-100/microRNA-125b is associated with lymph node metastasis in early colorectal cancer with submucosal invasion.

A majority of early colorectal cancers (CRCs) with submucosal invasion undergo surgical operation, despite a very low incidence of lymph node metastasis. Our study aimed to identify microRNAs (miRNAs) specifically responsible for lymph node metastasis in submucosal CRCs. MicroRNA microarray analysis revealed that miR-100 and miR-125b expression levels were significantly lower in CRC tissues with lymph node metastases than in those without metastases. These results were validated by quantitative real-time PCR in a larger set of clinical samples. The transfection of a miR-100 or miR-125b inhibitor into colon cancer HCT116 cells significantly increased cell invasion, migration, and MMP activity. Conversely, overexpression of miR-100 or miR-125b mimics significantly attenuated all these activities but did not affect cell growth. To identify target mRNAs, we undertook a gene expression array analysis of miR-100-silenced HCT116 cells as well as negative control cells. The Ingenuity Pathway Analysis, TargetScan software analyses, and subsequent verification of mRNA expression by real-time PCR identified mammalian target of rapamycin (mTOR) and insulin-like growth factor 1 receptor (IGF1R) as direct, and Fas and X-linked inhibitor-of-apoptosis protein (XIAP) as indirect candidate targets for miR-100 involved in lymph node metastasis. Knockdown of each gene by siRNA significantly reduced the invasiveness of HCT116 cells. These data clearly show that downregulation of miR-100 and miR-125b is closely associated with lymph node metastasis in submucosal CRC through enhancement of invasion, motility, and MMP activity. In particular, miR-100 may promote metastasis by upregulating mTOR, IGF1R, Fas, and XIAP as targets. Thus, miR-100 and miR-125b may be novel biomarkers for lymph node metastasis of early CRCs with submucosal invasion.

Response Predictors of S-1, Cisplatin, and Docetaxel Combination Chemotherapy for Metastatic Gastric Cancer: Microarray Analysis of Whole Human Genes.

OBJECTIVES: The aim of this study was to identify biomarkers for predicting the efficacy of docetaxel, cisplatin, and S-1 (DCS) therapy for advanced gastric cancer using microarrays of biopsy specimens before chemotherapy. METHODS: Nineteen samples were taken from 19 patients with unresectable metastatic gastric cancer who received DCS as a first-line therapy. Laser capture microdissection was performed, and total cellular RNA was extracted from each microdissected sample. Whole-gene expression was analyzed by microarray, and the difference in mRNA expression observed with the microarrays was confirmed by quantitative real-time PCR. Immunohistochemical staining was performed using clinical tissue sections obtained by endoscopic biopsy. RESULTS: Eleven patients were identified as early responders and 8 patients as nonresponders to DCS therapy. Twenty-nine genes showed significant differences in relative expression ratios between tumor and normal tissues. A classifier set of 29 genes had high accuracy (94.7%) for distinguishing gene expression between 11 early responders and 8 nonresponders. Decreasing the size of the classifier set to 4 genes (PDGFB, PCGF3, CISH, and ANXA5) increased the accuracy to 100%. Expression levels by real-time PCR for validation were well correlated with those 4 genes in microarrays. CONCLUSION: The genes identified may serve as efficient biomarkers for personalized cancer-targeted therapy.

Clinicopathological characteristics of serrated polyps as precursors to colorectal cancer: Current status and management.

Serrated polyps have long been thought to lack malignant potential in the human colorectum. However, identification of the serrated pathway to colorectal cancer based on molecular biology has improved our understanding of the pathogenesis of colorectal cancers. Accordingly, serrated polyps such as traditional serrated adenoma and sessile serrated adenoma/polyps (SSA/P) are now considered to be precursor lesions of the serrated pathway. Recently, serrated polyps were classified into three subtypes, consisting of hyperplastic polyp, SSA/P, and traditional serrated adenoma, according to the World Health Organization classification. It has been suggested that SSA/P in the proximal colon are a precursor lesion of pathogenesis of colorectal cancer and are characterized by BRAF mutation and a CpG island methylator phenotype with or without microsatellite instability. However, SSA/P is more challenging to detect by colonoscopy and is likely to account for some interval cancers, particularly in the proximal colon because it presents flat or sessile, isochroous appearance, and occasionally has a mucous cap. Furthermore, the possibility has been raised that pathologists misclassify SSA/P as hyperplastic polyp. It is important for gastroenterologists to recognize the endoscopic features of serrated polyps to facilitate their detection and removal and also to establish postpolypectomy surveillance guidelines. In this review, we discuss the recent classification of serrated polyps; the molecular characteristics of the serrated pathway; appropriate diagnostic methods using endoscopy, including a new image-enhanced endoscopic technique; and management of these lesions.

Clinicopathological Assessment of Gastric Xanthoma as Potential Predictive Marker of Gastric Cancer.

BACKGROUND/AIMS: Gastric xanthomas are frequently observed in the stomach as small yellowish plaques or nodules. A close relationship among Helicobacter pylori infection, atrophic gastritis, and xanthomas has been reported. We assessed the clinicopathological features of gastric cancer with or without xanthomas. METHODS: A total of 91 patients who were diagnosed as having early gastric cancer were enrolled. We evaluated the gastritis status using scores for gastritis and atrophy, positivity of H. pylori infection, the prevalence rate of xanthomas, and the clinicopathological features of gastric cancer. RESULTS: Gastric xanthomas were observed in 72.5% of early gastric cancer cases. Scores for gastritis and atrophy were significantly higher in the xanthoma-positive group than those in the xanthoma-negative group. A higher prevalence of differentiated-type adenocarcinoma was found in the xanthoma-positive group. Among the cases with multiple gastric xanthomas, the prevalence of males was significantly higher than that of females. CONCLUSION: A high prevalence rate of gastric xanthomas in gastric cancer cases was shown. Xanthomas were highly associated with age, the severities of gastritis and atrophy, and differentiated-type adenocarcinoma. Regardless of the eradication of H. pylori, xanthomas may be useful predictive markers for the development of differentiated-type adenocarcinoma.

Efficacy of hybrid endoscopic submucosal dissection (ESD) as a rescue treatment in difficult colorectal ESD cases.

BACKGROUND AND AIM: Endoscopic submucosal dissection (ESD), which provides a higher en bloc resection rate than conventional endoscopic mucosal resection (EMR), is considered to be a useful treatment option for large colorectal tumors. However, colorectal ESD is not widely used because of its technical difficulty, risk of complications and time required. To overcome these drawbacks, a simpler modified technique, ESD with snaring (hybrid ESD), has been developed. The aim of the present study was to retrospectively compare the safety and efficacy of hybrid ESD and conventional ESD for colorectal tumors. METHODS: Between September 2008 and June 2016, ESD was carried out on 137 lesions and hybrid ESD on 27 lesions. All hybrid ESD cases were carried out as a rescue treatment in difficult ESD cases. We retrospectively investigated procedure time, and the rates of en bloc resection, perforation, bleeding, and local recurrence. RESULTS: In the hybrid ESD group, procedure time was shorter compared with the ESD group (108 ± 59.5 min vs 122 ± 72.2 min), but the en bloc resection rate was lower (66.7% vs 94.2%). However, there were no significant differences in procedure time, or in rates of en bloc resection, perforation and bleeding between the two groups. Local recurrence did not develop in any of our cases. CONCLUSIONS: Hybrid ESD as a rescue treatment in difficult ESD cases may be less effective for en bloc resection of large colorectal tumors. Indication for hybrid ESD may be limited to scheduled treatment from the outset and emergency cases with patients who present unstable vital signs during ESD.

Prognostic impact of HER2, EGFR, and c-MET status on overall survival of advanced gastric cancer patients.

BACKGROUND: This study was conducted to investigate whether human epidermal growth factor receptor 2 (HER2) status, epidermal growth factor receptor (EGFR) status, and c-MET status are independent prognostic factors for advanced gastric cancer patients who received standard chemotherapy. METHOD: Unresectable or recurrent gastric or gastroesophageal junction cancer patients with histologically confirmed adenocarcinoma treated with S-1 plus cisplatin as first-line chemotherapy were eligible. Formalin-fixed paraffin-embedded tumor samples were examined for HER2, EGFR, and c-MET status using immunohistochemistry (IHC). Additionally, gene amplification was examined using fluorescent in situ hybridization (FISH) for HER2. Positivity was defined as an IHC score of 3+ or an IHC score of 2+/FISH positive for HER2, and an IHC score of 2+ or 3+ for both EGFR and c-MET. RESULTS: Of the 293 patients from nine institutions, 43 (15%) were HER2 positive, 79 (27%) were EGFR positive, and 120 (41%) were c-MET positive. Ten patients (3%) showed positive co-expression of HER2, EGFR, and c-MET. After a median follow-up time of 58.4 months with 280 deaths, there was no significant difference in overall survival (OS) in terms of HER2 and EGFR status. However, there was a significant difference in OS between c-MET-positive and c-MET-negative patients [median, 11.9 months vs 14.2 months; hazard ratio, 1.31 (95% confidence interval, 1.03-1.67); log-rank P = 0.024]. Multivariate analysis also showed that c-MET positivity was still a prognostic factor for OS [hazard ratio, 1.30 (95% confidence interval, 1.02-1.67); P = 0.037]. CONCLUSIONS: The study suggested that c-MET-positive status had poor prognostic value. These data could be used as the basis for future clinical trials for targeting agents for advanced gastric cancer patients.

Serum diamine oxidase activity as a predictor of gastrointestinal toxicity and malnutrition due to anticancer drugs.

BACKGROUND AND AIM: Objective evaluation of intestinal mucosal damage due to anticancer drugs is generally difficult. Serum diamine oxidase (DAO) activity is reported to reflect the integrity and maturity of the small intestinal mucosa. Therefore, we investigated whether serum DAO activity is an indicator of gastrointestinal toxicity or nutritional status in patients receiving chemotherapy. METHODS: We prospectively enrolled 20 patients with unresectable metastatic gastric cancer who received oral S-1 (80 mg/m(2) ) on days 1-14, and intravenous cisplatin (60 mg/m(2) ) and docetaxel (50 mg/m(2) ) on day 8 every 3 weeks. Serum DAO activity was measured by colorimetry. Gastrointestinal toxicity was evaluated by Common Toxicity Criteria for Adverse Events version 4.0. Endoscopic examination and biopsy of duodenal mucosa assessed mucosal damage. Malnutrition was evaluated by measuring serum total protein and albumin levels. RESULTS: Serum DAO activity decreased step-by-step significantly during anticancer drug treatment and recovered after drug holidays. In all 14 patients who experienced diarrhea, serum DAO activity significantly decreased prior to diarrhea onset. Percent decrease in DAO activity was significantly correlated with severity of diarrhea. Significant correlation was observed between percent decrease in DAO activity and percent decrease in duodenal villus height or surface area from baseline. There were also significant correlations between percent decrease in serum DAO activity at day 14 and percent decrease in serum total protein or albumin levels at day 21 from baseline. CONCLUSION: Serum DAO activity sensitively indicates gastrointestinal damage prior to symptom onset and can be a useful predictor of intestinal mucosal damage and nutritional status in patients receiving chemotherapy.

High antitumor activity of pladienolide B and its derivative in gastric cancer.

The antitumor activity of pladienolide B, a novel splicing inhibitor, against gastric cancer is totally unknown and no predictive biomarker of pladienolide B efficacy has been reported. We investigated the antitumor activity of pladienolide B and its derivative on gastric cancer cell lines and primary cultured cancer cells from carcinomatous ascites of gastric cancer patients. The effect of pladienolide B and its derivative on six gastric cancer cell lines was investigated using a MTT assay and the mean IC50 values determined to be 1.6 ± 1.2 (range, 0.6-4.0) and 1.2 ± 1.1 (range, 0.4-3.4) nM, respectively, suggesting strong antitumor activity against gastric cancer. The mean IC50 value of pladienolide B derivative against primary cultured cells from 12 gastric cancer patients was 4.9 ± 4.7 nM, indicative of high antitumor activity. When 18 SCID mice xenografted with primary cultured cells from three patients were administered the pladienolide B derivative intraperitoneally, all tumors completely disappeared within 2 weeks after treatment. Histological examination revealed a pathological complete response for all tumors. In the xenograft tumors after treatment with pladienolide B derivative, immature mRNA were detected and apoptotic cells were observed. When the expressions of cell-cycle proteins p16 and cyclin E in biopsied gastric cancer specimens were examined using immunohisctochemistry, positivities for p16 and cyclin E were significantly and marginally higher, respectively, in the low-IC50 group compared with the high-IC50 group, suggesting the possibility that they might be useful as predictive biomarkers for pladienolide B. In conclusion, pladienolide B was very active against gastric cancer via a mechanism involving splicing impairment and apoptosis induction.

Suppressive effect of RAS inhibitor manumycin A on aberrant crypt foci formation in the azoxymethane-induced rat colorectal carcinogenesis model.

BACKGROUND AND AIM: The chemopreventive effect of RAS inhibitors on colorectal cancer is unknown. Because aberrant crypt foci (ACF), earliest preneoplastic lesions, are highly positive for K-RAS mutation, RAS inhibitors are likely to be effective for chemoprevention. Therefore, in the present study, the suppressive effect of a RAS inhibitor, manumycin A, on ACF formation in an azoxymethane (AOM)-induced rat colorectal carcinogenesis model was investigated. METHODS: Rats injected with AOM were administered manumycin A (30 mg/kg) subcutaneously thrice weekly for 8 weeks or for 4 weeks (latter half), sacrificed at 8 weeks, and examined for ACF in the colorectum. Phosphorylated ERK and Ki-67 expression was evaluated by immunohistochemistry. Apoptosis was assessed by TUNEL staining. RESULTS: The mean number of ACF in the 8-week manumycin A group (72.9 ± 20.1) was significantly lower than in the vehicle group (155.6 ± 56.7, P < 0.01), and it was significantly lower even in the 4-week manumycin A group than in the vehicle group (92.2 ± 13.0 vs 222.3 ± 83.3, P < 0.01). The positive rate for phosphorylated ERK in the manumycin A group (13.5 ± 19.2%) was significantly lower than in the vehicle group (50.2 ± 19.8%, P < 0.01). The positive rate for Ki-67 in the manumycin A group (2.2 ± 3.4%) was significantly lower than in the vehicle group (14.7 ± 8.2%, P < 0.01). There were significantly more terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling-positive cells in tissue samples from the manumycin A group versus the vehicle group (8.6 ± 9.7% vs 2.9 ± 2.0%, P < 0.05). CONCLUSION: Manumycin A suppressed ACF formation in the AOM-induced colorectal carcinogenesis model, demonstrating that RAS inhibitors may be very effective for chemoprevention of colorectal cancers.

Clinical benefit of high-sensitivity KRAS mutation testing in metastatic colorectal cancer treated with anti-EGFR antibody therapy.

OBJECTIVE: We compared high-sensitivity KRAS mutation testing with direct sequencing for predicting the efficacy of antiepidermal growth factor receptor antibodies in patients with metastatic colorectal cancer (mCRC). METHODS: We analyzed the KRAS status in 61 tumors from cetuximab-treated mCRC patients by both direct sequencing and a high-sensitivity method: 2-step PCR restriction fragmentation length polymorphism (RFLP). Therapeutic effects in each mutational status were evaluated. RESULTS: The incidences of KRAS mutations determined by direct sequencing and 2-step PCR RFLP were 34.4 and 52.5%, respectively (p = 0.02). Patients were categorized into 3 groups [W/W, wild-type by both methods (n = 29); W/M, wild-type by direct sequencing, detected mutation by 2-step PCR RFLP (n = 11); M/M, mutant-type by both methods (n = 21)]. The response rate for cetuximab in the W/M group (0%) was the same as that in the M/M group, and was significantly lower than in the W/W group (41.4%) (p < 0.001). Progression-free survival in the W/M group (11.0 weeks) was similar to that in the M/M group (8.0 weeks), and was significantly shorter than in the W/W group (18.0 weeks) (p < 0.002). CONCLUSION: High-sensitivity KRAS mutation testing is useful for selecting true responders to cetuximab.

Endoscopic submucosal dissection for early gastric cancer using a cross-counter technique.

BACKGROUND AND STUDY AIMS: Endoscopic submucosal dissection (ESD) in early gastric cancer has rapidly come into widespread use. However, since complications such as bleeding and perforation often occur, and the procedure time is longer for ESD than endoscopic mucosal resection (EMR), development of safer and more reliable technique is required. PATIENTS AND METHODS: The subjects comprised 45 patients with lesions diagnosed histologically as early gastric cancer. They were divided into three groups: cross-counter technique group (CC, n = 15), peroral traction-assisted ESD with suture material group (PT, n = 15), and no-traction group (NT, n = 15). ESD was carried out by two endoscopists who had experienced fewer than 30 cases of ESD. To compare safety and efficacy of a new traction method (CC group) for ESD in early gastric cancer with other methods (PT group and NT group), procedure time, dissected area per unit time, complete resection rate, perforation rate, and bleeding rate were evaluated. RESULTS: There was no significant difference among these three groups in terms of complications, complete resection rate or procedure time. The dissection area per unit time was 22.4, 15.7, and 13.5 mm(2)/min in the CC, PT, and NT groups, respectively, and there was a significant difference between the CC and NT groups (p = 0.007). CONCLUSIONS: The cross-counter technique shortened the treatment time for endoscopists without abundant experience in gastric ESD, and it is considered a useful method to institute in order to introduce ESD.

Endoscopic submucosal dissection for large colorectal tumors using a cross-counter technique and a novel large-diameter balloon overtube.

BACKGROUND AND AIM: Endoscopic submucosal dissection (ESD) in early gastric cancer (EGC), which provides a higher complete resection rate than conventional endoscopic mucosal resection (EMR), has rapidly come into widespread use. However, colorectal ESD is not widely used because of its technical difficulty and complications such as perforation, and the procedure time is longer than that of conventional EMR. Development of safer and more reliable devices as well as technique modifications are therefore required. The aim of our study is to compare safety and efficacy of a new traction method, the cross-counter technique, for large colorectal tumors combined with a balloon overtube. METHODS: A total of 30 patients with large colorectal tumors were analyzed retrospectively; 15 patients for the cross-counter technique group (CC group) and 15 patients for the no-traction group (NT group). Procedure time, complete resection rate, perforation rate and bleeding rate were assessed. RESULTS: The procedure time was 126 ± 42.2 min and 165 ± 61.3 min in the CC and NT groups, respectively, and there was a significant difference between the two groups (P < 0.05). There were no significant differences in complete resection rate, perforation rate and bleeding rate between the two groups. CONCLUSION: The cross-counter technique shortened the treatment time in colorectal ESD without any complication.

Endoscopic ablation therapy for gastrointestinal superficial neoplasia.

AIM: In Japan, endoscopic mucosal resection (EMR) and endoscopic submucosal dissection (ESD) have been widely accepted and standardized for the treatment of gastrointestinal superficial neoplasia. METHODS: In contrast, mucosal ablation techniques are more common in Western countries and a variety of endoscopic ablation modalities, including argon plasma coagulation (APC), photodynamic therapy (PDT) and lasers, are used. RESULTS: Recently developed modalities such as radiofrequency ablation (RFA) and cryotherapy are also available for the treatment of superficial lesions such as dysplasia of Barrett's esophagus. CONCLUSION: Although we should understand that the completeness of destruction of neoplastic tissue can only be judged at follow up, endoscopic ablation is a viable alternative to endoscopic resection for dysplasia and early-stage malignancies, especially for poor candidates of surgery or endoscopic resection.

[Successful rituximab monotherapy in a patient with mucosa-associated lymphoid tissue lymphoma of the rectum with trisomy 3, 18].

A 62-year-old man was referred to our hospital with enlargement of mucosa-associated lymphoid tissue (MALT) lymphoma of the rectum after the eradication of Helicobacter pylori. The patient was given a diagnosis of stage I MALT. Endoscopic observation revealed an enlarged rectal tumor with 3, 18 double trisomy. Rituximab monotherapy was given and complete remission was achieved. Rituximab monotherapy can be useful for MALT lymphoma of the rectum.

Massive hemobilia following plastic stent removal in common bile duct cancer associated with primary sclerosing cholangitis (with video).

Hemobilia is defined as bleeding into the biliary tract. Herein, we report a very rare case of massive hemobilia following plastic stent (PS) removal in common bile duct (CBD) cancer. A 72-year-old man with primary sclerosing cholangitis had undergone repeated insertion of a PS into the CBD. Biliary tract biopsy was performed based on suspicion of combined CBD cancer. Biopsy revealed poorly differentiated adenocarcinoma of the CBD. One month after the biliary tract biopsy, he was admitted for acute cholangitis, and endoscopic retrograde cholangiography was performed for the exchange of the PS. When one of the two biliary PSs was removed, spurting bleeding from the major papilla began abruptly. The massive bleeding caused the patient to be in a pre-shock state. A retrieval balloon catheter was compressed against the papilla for hemostasis. Although he was treated conservatively, the patient developed a bloody discharge. Upper gastrointestinal endoscopy revealed that the pulsatile bleeding beside the PSs started immediately after the removal of the coagula. Emergent contrast-enhanced computed tomography showed right hepatic artery aneurysm across the CBD. Therefore, transarterial embolization was performed. The patient's post-therapeutic course was uneventful. He received chemotherapy, but died about a half year after hemobilia occurred.