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.

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.

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.

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.

Detection of aberrant crypt foci with image-enhanced endoscopy.

Background and study aims Conventional detection of aberrant crypt foci (ACF) with dye-spraying and magnifying observation is labor- and skill-intensive. We performed a prospective non-inferiority study to investigate the utility of image-enhanced endoscopy (IEE) for detection of ACF. Patients and methods Patients with a history of colorectal neoplasm were eligible. The number of ACF in the lower rectum was counted first using IEE magnification with narrow-band imaging (NBI) or blue-laser imaging (BLI), and subsequently using the methylene blue method. The primary endpoint was the ACF detection rate with IEE, i. e., the number of ACF detected with IEE relative to the number of ACF detected with methylene blue. The secondary endpoints were bowel preparation time, ACF detection time, and the detection rate with NBI or BLI. Results A total of 40 patients were enrolled (NBI 20 and BLI 20). The overall detection rate for ACF with IEE was 81.7 % (503/616; 95 %CI 78.8 - 84.6 %), meeting the primary endpoint. The detection rate for ACF with BLI (84.9 %, 258/304) was significantly higher than with NBI (78.5 %, 245/312; P  < 0.05). Both bowel preparation time and ACF detection time were significantly shorter with IEE versus the methylene blue method ( P  < 0.01, respectively). The detection rates for dysplastic and non-dysplastic ACF with IEE were 84.4 % (27/32) and 80.3 % (469/584), respectively. Conclusion IEE is able to detect ACF during colonoscopy with sensitivity non-inferior to that of the conventional methylene blue method. IEE is simpler than the methylene blue method and is therefore a potentially useful new tool for ACF detection.

Linked color imaging enhances endoscopic detection of sessile serrated adenoma/polyps.

BACKGROUND AND STUDY AIMS: Although new image-enhanced endoscopy (IEE) technologies such as blue laser imaging (BLI), BLI-bright, and linked color imaging (LCI) have been developed, their utility for the detection of sessile serrated adenoma/polyps (SSA/Ps) is still unclear. This study aimed to evaluate the utility of BLI, BLI-bright, and LCI for SSA/P detection in still image examinations and in a prospective randomized controlled trial (RCT). PATIENTS AND METHODS: A group of 6 expert and non-expert endoscopists read 200 endoscopic still images containing SSA/P lesions using white light image (WLI), BLI, BLI-bright, and LCI. Color differences were calculated using the color space method. A prospective RCT of tandem colonoscopy with WLI and LCI was performed. Patients with SSA/P and those with a history of SSA/P that had been endoscopically removed were enrolled and randomly allocated to WLI-LCI or LCI-WLI groups. Additional endoscopic detection rates for SSA/P were compared between the 2 groups. RESULTS: LCI showed the highest SSA/P detection rate among the 4 modes for both expert and non-expert endoscopists. The detection rate with LCI for the 6 expert endoscopists (mean 98.3 ±â€Šstandard deviation 2.0 %) was significantly higher than that with WLI (86.7 ±â€Š6.0 %, P  < 0.01). Likewise, the detection rate with LCI for the 6 non-expert endoscopists (92.3 ±â€Š2.9 %) was significantly higher than that with WLI (72.7 ±â€Š11.5 %, P  < 0.01). The color difference of SSA/P with LCI was the highest among the 4 modes, and was significantly higher than with WLI (median 15.9, (interquartile range 13.7 - 20.6) vs. 10.2, (7.6 - 14.2); P  < 0.0001). In the RCT, a total of 44 patients (WLI-LCI 22 vs. LCI-WLI 22) underwent colonoscopy. The additional detection rate for SSA/P in the second inspection in the WLI-LCI group (21.6 %, 8/37) was significantly higher than in the LCI-WLI group (3.2 %, 1/31; P  = 0.02). The small, flat, non-mucus and isochromatic SSA/Ps in the transverse colon were detected more frequently in the second inspection with LCI. CONCLUSIONS: LCI was the most sensitive mode for SSA/P detection among WLI, BLI, BLI-bright, and LCI in the still image examinations. Our RCT strongly suggests that LCI is superior to conventional WLI for SSA/P detection during colonoscopy. UMIN000017599.

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.

Molecular imaging of aberrant crypt foci in the human colon targeting glutathione S-transferase P1-1.

Aberrant crypt foci (ACF), the earliest precursor lesion of colorectal cancers (CRCs), are a good surrogate marker for CRC risk stratification and chemoprevention. However, the conventional ACF detection method with dye-spraying by magnifying colonoscopy is labor- and skill-intensive. We sought to identify rat and human ACF using a fluorescent imaging technique that targets a molecule specific for ACF. We found that glutathione S-transferase (GST) P1-1 was overexpressed in ACF tissues in a screening experiment. We then synthesized the fluorogenic probe, DNAT-Me, which is fluorescently quenched but is activated by GSTP1-1. A CRC cell line incubated with DNAT-Me showed strong fluorescence in the cytosol. Fluorescence intensities correlated significantly with GST activities in cancer cell lines. When we sprayed DNAT-Me onto colorectal mucosa excised from azoxymethane-treated rats and surgically resected from CRC patients, ACF with strong fluorescent signals were clearly observed. The ACF number determined by postoperative DNAT-Me imaging was almost identical to that determined by preoperative methylene blue staining. The signal-to-noise ratio for ACF in DNAT-Me images was significantly higher than that in methylene blue staining. Thus, we sensitively visualized ACF on rat and human colorectal mucosa by using a GST-activated fluorogenic probe without dye-spraying and magnifying colonoscopy.

EGFR Downregulation after Anti-EGFR Therapy Predicts the Antitumor Effect in Colorectal Cancer.

Anti-EGFR mAb is reported to induce EGFR internalization in colorectal cancer cells. However, the biological relevance of EGFR internalization with anti-EGFR mAb is unknown. Therefore, the relevance of EGFR downregulation with anti-EGFR mAb to antitumor activity in colorectal cancer cells was investigated. Quantification of EGFR on the cell surface before cetuximab treatment was assessed by flow cytometry, and its growth-inhibitory effects were measured by Trypan blue exclusion, in 10 RAS, BRAF wild-type colorectal cancer cell lines, but there was no significant correlation between EGFR number and its growth-inhibitory effect. However, a significant correlation existed between the percentage decrease in the number of EGFRs after cetuximab treatment and its growth-inhibitory effect in those cell lines. Treatment with TGFα, a ligand for EGFR, induced EGFR internalization in colorectal cancer cells, but most EGFRs subsequently recycled to the cell surface, consistent with previous studies. While cetuximab treatment induced EGFR internalization, most receptors subsequently translocated into the late endosome, leading to lysosomal degradation, as revealed by immunoblotting and double immunofluorescence. Cetuximab-sensitive colorectal cancer cells showed greater EGFR internalization, stronger cell growth inhibition, and more augmented apoptotic signals than nonsensitive cells. IHC for EGFR, performed using an EGFR pharmDx Kit (mouse anti-human EGFR mAb clone 2-18C9), in clinical specimens before and after anti-EGFR mAb therapy in 13 colorectal cancer patients showed a significant correlation between the response to anti-EGFR mAb and decreased staining after therapy.Implications: This report clearly demonstrates that anti-EGFR mAb facilitates internalization and subsequent degradation of EGFRs in lysosomes, which is an important determinant of the efficacy of anti-EGFR mAb treatment for colorectal cancer. Mol Cancer Res; 15(10); 1445-54. ©2017 AACR.

Paraneoplastic Hypocalcemia Developed in Gastric Cancer Accompanied by Osteoblastic Metastasis.

Paraneoplastic syndromes are generally defined as clinical disorders associated with malignant diseases, and hypocalcemia associated with cancer is a rare condition. A woman in her 60s was referred to our hospital for the further examination of massive ascites due to carcinoma of unknown primary origin. She complained of numbness around her lips, and marked hypocalcemia of 5.0 mg/dL was noted. After two courses of chemotherapy, computed tomography showed a decrease in the ascites, and her serum calcium level increased. Although hypocalcemia is a very rare condition in patients with gastric cancer, serum calcium values should be evaluated when neurological symptoms are observed.

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.

The impacts of computer adaptive testing from a variety of perspectives.

Computer adaptive testing (CAT) is a kind of tailored testing, in that it is a form of computer-based testing that is adaptive to each test-taker's ability level. In this review, the impacts of CAT are discussed from different perspectives in order to illustrate crucial points to keep in mind during the development and implementation of CAT. Test developers and psychometricians often emphasize the efficiency and accuracy of CAT in comparison to traditional linear tests. However, many test-takers report feeling discouraged after taking CATs, and this feeling can reduce learning self-efficacy and motivation. A trade-off must be made between the psychological experiences of test-takers and measurement efficiency. From the perspective of educators and subject matter experts, nonstatistical specifications, such as content coverage, content balance, and form length are major concerns. Thus, accreditation bodies may be faced with a discrepancy between the perspectives of psychometricians and those of subject matter experts. In order to improve test-takers' impressions of CAT, the author proposes increasing the target probability of answering correctly in the item selection algorithm even if doing so consequently decreases measurement efficiency. Two different methods, CAT with a shadow test approach and computerized multistage testing, have been developed in order to ensure the satisfaction of subject matter experts. In the shadow test approach, a full-length test is assembled that meets the constraints and provides maximum information at the current ability estimate, while computerized multistage testing gives subject matter experts an opportunity to review all test forms prior to administration.

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.

Twin Rectal Tonsils Mimicking Carcinoid or Mucosa-Associated Lymphoid Tissue Lymphoma.

The rectal tonsil is a rare polypoid lesion exclusively found in the rectum and is considered a reactive proliferation of the lymphoid tissue. Although this lesion is benign, we recommend that it should be differentiated from carcinoid or polypoid type of mucosa-associated lymphoid tissue lymphomas, based on gross findings. In this case report, we describe a case of rectal lesions with a unique appearance in a 41-year-old man. Colonoscopy revealed two 5-mm-sized nodules located opposite from each other on the left and right sides of the lower rectum. Endoscopic mucosal resection was conducted. Histopathologically, both lesions were mainly located in the submucosa and consisted of prominent lymphoid follicles with germinal centers of various sizes. No immunoreactivity of Bcl-2 was seen in the germinal centers. Immunohistochemical staining for kappa and lambda light chains revealed a polyclonal pattern. Therefore, these lesions were diagnosed as rectal tonsils.

Duodenal cancer in a young patient with Peuts-Jeghers syndrome harboring an entire deletion of the STK11 gene.

A 21-year-old woman with Peuts-Jeghers syndrome (PJS) was referred to our hospital for gastrointestinal surveillance. She had been diagnosed as having PJS from a young age based on her family history and the presence of mucocutaneous pigmentation on her lips and oral mucosa. Her mother and brother had PJS harboring an entire deletion of the STK11 gene. She had tetralogy of Fallot, atrial tachycardia, sick sinus syndrome, and mental retardation in her past history. Esophagogastroduodenoscopy identified a protruded lesion with a depressed area that occupied the lumen half-circumferentially in the duodenal second portion and also showed a 10-mm protruded lesion on the anterior wall of the lower gastric body. Colonoscopy revealed a 3-mm protruded lesion on the rectum. No polyp was found in a barium small bowel series. Biopsies were taken from the duodenal tumor and gastric and colon polyps. Histopathologically, the duodenal tumor revealed a well-differentiated tubular adenocarcinoma, whereas gastric and colon polyps showed hamartomatous polyp. Therefore, subtotal stomach-preserving pancreatoduodenectomy was performed, and subsequent histopathological examination revealed that the duodenal tumor consisted of hamartomatous polyp and a well-differentiated tubular adenocarcinoma with invasion to the muscularis propria. Immunohistochemistry revealed accumulation of nuclear p53 protein, but no accumulation of nuclear ß-catenin protein. No RAS mutation was detected. Furthermore, direct sequencing of the STK11 gene in genomic DNA from peripheral blood mononuclear cells did not detect any mutation initially. However, multiplex ligation-dependent probe amplification (MLPA) analysis revealed entire deletion of STK11. These findings suggest that entire deletion of the STK11 gene caused hamartomatous polyps in the entire gastrointestinal tract and, subsequently, duodenal polyps likely gave rise to cancer through p53 mutation.

Hemosuccus pancreaticus caused by a mucinous cystic neoplasm of the pancreas.

Hemosuccus pancreaticus is a gastrointestinal hemorrhage through the main pancreatic duct. Here, we report a rare case of hemosuccus pancreaticus due to a mucinous cystic neoplasm of the pancreas. A 62-year-old woman who had been followed for a branch duct intraductal papillary mucinous neoplasm visited our emergency room due to severe abdominal pain and bloody discharge. Computed tomography revealed that the pancreatic cyst increased the tension of the wall and a high-density area indicative of bleeding into the cyst was observed. Endoscopy showed opening of and hemorrhaging from the papilla of Vater. The patient was diagnosed with hemosuccus pancreaticus caused by hemorrhaging into the cyst from the branch duct intraductal papillary mucinous neoplasm. Based on this diagnosis, elective distal pancreatectomy was performed. The histopathological diagnosis was a mucinous cystic neoplasm with intermediate-grade dysplasia based upon the pathological findings that fibrous ovarian-type stroma existed abundantly and the stroma cells were positive for progesterone receptor and inhibin. Hemosuccus pancreaticus caused by a mucinous cystic neoplasm is extremely rare and there has been only one case reported to date. In conclusion, it should be recognized that pancreatic cystic neoplasms including mucinous cystic neoplasms may cause hemosuccus pancreaticus.

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.

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.

Influence of metabolic syndrome on upper gastrointestinal disease.

A recent increase in the rate of obesity as a result of insufficient physical exercise and excess food consumption has been seen in both developed and developing countries throughout the world. Additionally, the recent increased number of obese individuals with lifestyle-related diseases associated with abnormalities in glucose metabolism, dyslipidemia, and hypertension, defined as metabolic syndrome (MS), has been problematic. Although MS has been highlighted as a risk factor for ischemic heart disease and arteriosclerotic diseases, it was also recently shown to be associated with digestive system disorders, including upper gastrointestinal diseases. Unlike high body weight and high body mass index, abdominal obesity with visceral fat accumulation is implicated in the onset of various digestive system diseases because excessive visceral fat accumulation may cause an increase in intra-abdominal pressure, inducing the release of various bioactive substances, known as adipocytokines, including tumor necrosis factor-α, interleukin-6, resistin, leptin, and adiponectin. This review article focuses on upper gastrointestinal disorders and their association with MS, including obesity, visceral fat accumulation, and the major upper gastrointestinal diseases.

Neuroendocrine carcinoma of the pancreas with similar genetic alterations to invasive ductal adenocarcinoma.

Neuroendocrine carcinoma (NEC) of the pancreas is very rare, and its origin is not fully elucidated. Here, we present a case of a small-size NEC of the pancreas that is genetically similar to invasive ductal adenocarcinoma (IDA). A 65-year-old man was referred to our hospital due to obstructive jaundice and found to have a 12-mm solid tumor in the pancreas head. The tumor exhibited low vascularity on enhanced computed tomography, and endoscopic retrograde pancreatographic imaging revealed an irregular obstruction in a branch duct of the pancreas. The patient was thereby diagnosed with a pancreatic ductal cancer, and stomach-preserving pancreaticoduodenectomy with regional lymph node resection was performed. Histochemical analysis of the resected tumor showed that the neoplastic cells with scanty cytoplasm and hyperchromatic nuclei strongly expressed chromogranin A and synaptophysin. The Ki-67 index was 40 % in the most proliferative tumor regions, and the tumor was diagnosed as a NEC of the pancreas. However, in the analysis of genetic alterations of the tumor tissue, the neoplastic cells showed altered KRAS, TP53, and SMAD4/DPC4, suggesting that the NEC in our case is genetically related to IDA. Our data suggest that poorly differentiated IDAs may transform into NECs.