Propulsive colonic contractions are mediated by inhibition-driven poststimulus responses that originate in interstitial cells of Cajal.

The peristaltic reflex is a fundamental behavior of the gastrointestinal (GI) tract in which mucosal stimulation activates propulsive contractions. The reflex occurs by stimulation of intrinsic primary afferent neurons with cell bodies in the myenteric plexus and projections to the lamina propria, distribution of information by interneurons, and activation of muscle motor neurons. The current concept is that excitatory cholinergic motor neurons are activated proximal to and inhibitory neurons are activated distal to the stimulus site. We found that atropine reduced, but did not block, colonic migrating motor complexes (CMMCs) in mouse, monkey, and human colons, suggesting a mechanism other than one activated by cholinergic neurons is involved in the generation/propagation of CMMCs. CMMCs were activated after a period of nerve stimulation in colons of each species, suggesting that the propulsive contractions of CMMCs may be due to the poststimulus excitation that follows inhibitory neural responses. Blocking nitrergic neurotransmission inhibited poststimulus excitation in muscle strips and blocked CMMCs in intact colons. Our data demonstrate that poststimulus excitation is due to increased Ca2+ transients in colonic interstitial cells of Cajal (ICC) following cessation of nitrergic, cyclic guanosine monophosphate (cGMP)-dependent inhibitory responses. The increase in Ca2+ transients after nitrergic responses activates a Ca2+-activated Cl− conductance, encoded by Ano1, in ICC. Antagonists of ANO1 channels inhibit poststimulus depolarizations in colonic muscles and CMMCs in intact colons. The poststimulus excitatory responses in ICC are linked to cGMP-inhibited cyclic adenosine monophosphate (cAMP) phosphodiesterase 3a and cAMP-dependent effects. These data suggest alternative mechanisms for generation and propagation of CMMCs in the colon.

Empirical Therapy Versus Tailored Therapy of Helicobacter pylori in Korea: Results of the K-CREATE Study.

BACKGROUND: The optimal duration of regimens for tailored therapy based on genotypic resistance for clarithromycin has yet to be established. AIM: This study was a nationwide, multicenter, randomized trial comparing empirical therapy with tailored therapy based on genotypic resistance for first-line eradication of Helicobacter pylori. We also compared the eradication rates of 7- and 14-day regimens for each group. PATIENTS AND METHODS: Patients with H. pylori infection were first randomized to receive empirical or tailored therapy. Patients in each group were further randomized into 7- or 14-day regimens. Empirical therapy consisted of a triple therapy (TT) regimen (twice-daily doses of pantoprazole 40 mg, amoxicillin 1 g, and clarithromycin 500 mg) for 7 or 14 days. Tailored therapy consisted of TT of 7 or 14 days in patients without genotypic resistance. Patients with genotypic resistance were treated with bismuth quadruple therapy (BQT) regimens (twice-daily doses of pantoprazole 40 mg, three daily doses of metronidazole 500 mg, and four times daily doses of bismuth 300 mg and tetracycline 500 mg) for 7 or 14 days. A 13C-urea breath test assessed eradication rates. The primary outcome was eradication rates of each group. RESULTS: A total of 593 patients were included in the study. The eradication rates were 65.7% (201/306) in the empirical therapy group and 81.9% (235/287) in the tailored therapy group for intention-to-treat analysis (p < 0.001). In the per-protocol analysis, the eradication rates of the empirical therapy and tailored groups were 70.3% (201/286) and 85.5% (235/274) (p < 0.001), respectively. There was no difference in compliance between the two groups. The rate of adverse events was higher in the tailored group compared to the empirical group (p < 0.001). DISCUSSION: Our study confirmed that tailored therapy based on genotypic resistance was more effective than empirical therapy for H. pylori eradication in Korea. However, no significant difference was found between 7- and 14-day regimens for each group. Future studies are needed to determine the optimal duration of therapy for empirical and tailored therapy regimens.

Endoscopic Submucosal Dissection of Early Gastric Cancer in Patients with Liver Cirrhosis.

BACKGROUND AND OBJECTIVES: Endoscopic submucosal dissection (ESD) has become widely accepted method for treating early gastric cancer (EGC), but little is known about its role in patients with liver cirrhosis (LC). The aims of this study were to evaluate the outcomes of ESD in treating EGC in patients with LC. METHODS: The multicenter retrospective study identified 43 patients with chronic hepatitis B (CHB)-related cirrhosis undergoing ESD for treating EGC. The patients (LC group) were subdivided into two groups based on their Child-Pugh classification (CP-class): 32 with CP-class A (LC-A) and 11 with CP-class B (LC-B). The patients were compared to 47 non-cirrhotic CHB patients who underwent ESD (CHB group). Eight patients had a past history of hepatocellular carcinoma (HCC) prior to ESD, but no patients had viable HCC when ESD was performed. RESULTS: Procedural outcomes (en bloc, lateral/basal margins resection) and post-procedural complications (bleeding or perforation) did not differ significantly between the LC and CHB groups or between the LC-A and LC-B groups. No patients experienced worsening of the Child-Pugh score 1 month after ESD compared with the baseline score. During a median observation period of 66 months, the recurrence rates of gastric cancers were similar between the LC and CHB groups (5-year recurrence rates: 2.4 vs. 2.3%, p = 0.925), and all recurrent gastric cancers were completely resected by additional ESD. The overall mortality rate was increased in the LC group (5-year mortality rates: 17.9 vs. 5.7%, p = 0.034), and 8 of 10 deaths were attributed to liver-related diseases (such as HCC, complications of portal hypertension, hepatic failure). CONCLUSIONS: ESD is feasible in patients with EGC and comorbid LC, even those with CP-class B cirrhosis. Their prognosis depends on LC-related diseases and not recurrent EGC.

A Case of Taenia asiatica Infection Diagnosed by Colonoscopy.

A case of Taenia asiatica infection detected by small bowel series and colonoscopy is described. The patient was a 42-year-old Korean man accompanied by discharge of movable proglottids via anus. He used to eat raw pig liver but seldom ate beef. Small bowel series radiologic examinations showed flat tape-like filling defects on the ileum. By colonoscopy, a moving flat tapeworm was observed from the terminal ileum to the ascending colon. The tapeworm was identified as T. asiatica by mitochondrial DNA sequencing. The patient was prescribed with a single oral dose (16 mg/kg) of praziquantel.

Eradication Rates of Helicobacter pylori in Korea Over the Past 10 years and Correlation of the Amount of Antibiotics Use: Nationwide Survey.

BACKGROUND: The efficacy of proton-pump inhibitor-amoxicillin-clarithromycin therapy for H. pylori eradication has decreased over time. OBJECTIVE: We assessed the trend of H. pylori eradication rates over the last 10 years and the relationship between the eradication rates and the amount of macrolide antibiotic use in a country with a high prevalence of H. pylori infection. METHODS: This vast nationwide multicenter study was conducted with 34,139 adults treated for H. pylori infection from January 2001 to December 2010. The defined daily dose per km(2) (DSD) of macrolide antibiotics was calculated (n = 141,019) using the Health Insurance Review & Assessment data base from 2008 to 2010 in the two cities which had the lowest (Jeju city) or highest (Chuncheon city) eradication rate. RESULTS: The eradication rates of proton-pump inhibitor-amoxicillin-clarithromycin therapy ranged 84.9-87.5% from 2001 to 2007, and those of 2008 to 2010 ranged 80.0-81.4% with a decreasing trend (p < 0.0001). The decreasing trend of eradication rates for the overall first-line therapy was observed only in three of the seven geographic areas in Korea (p < 0.0001). The DSD of macrolide antibiotics was significantly higher in Jeju than Cheunchon city (0.85 vs 0.52, p < 0.0001). CONCLUSIONS: H. pylori eradication rates with clarithromycin-containing triple therapy in Korea showed a decreasing trend over the past 10 years, although the trend varied among geographic areas. This difference may be associated with the amount of macrolide antibiotic use.

Protease-activated receptors modulate excitability of murine colonic smooth muscles by differential effects on interstitial cells.

Protease-activated receptors (PARs) are G protein-coupled receptors activated by proteolytic cleavage at their amino termini by serine proteases. PAR activation contributes to the inflammatory response in the gastrointestinal (GI) tract and alters GI motility, but little is known about the specific cells within the tunica muscularis that express PARs and the mechanisms leading to contractile responses. Using real time PCR, we found PARs to be expressed in smooth muscle cells (SMCs), interstitial cells of Cajal (ICC) and platelet-derived growth factor receptor α positive (PDGFRα(+)) cells. The latter cell-type showed dominant expression of F2r (encodes PAR1) and F2rl1 (encodes PAR2). Contractile and intracellular electrical activities were measured to characterize the integrated responses to PAR activation in whole muscles. Cells were isolated and ICC and PDGFRα(+) cells were identified by constitutive expression of fluorescent reporters. Thrombin (PAR1 agonist) and trypsin (PAR2 agonist) caused biphasic responses in colonic muscles: transient hyperpolarization and relaxation followed by repolarization and excitation. The inhibitory phase was blocked by apamin, revealing a distinct excitatory component. Patch clamp studies showed that the inhibitory response was mediated by activation of small conductance calcium-activated K(+) channels in PDGFRα(+) cells, and the excitatory response was mediated by activation of a Cl(-) conductance in ICC. SMCs contributed little to PAR responses in colonic muscles. In summary, PARs regulate the excitability of colonic muscles; different conductances are activated in each cell type of the SMC-ICC-PDGFRα(+) cell (SIP) syncytium. Motor responses to PAR agonists are integrated responses of the SIP syncytium.

Prevalence and risk factors of functional dyspepsia: a nationwide multicenter prospective study in Korea.

GOALS: To evaluate the prevalence of functional dyspepsia (FD) and its risk factors. BACKGROUND: FD is a common disorder, but its negative influences greatly affect the quality of life. The predictive factors of FD are still ambiguous. STUDY: A total of 3399 participants underwent screening gastroscopy at one of 7 nationwide health care centers in Korea and who completed a questionnaire. Atrophic gastritis was defined by gastroscopy. Serologic Helicobacter pylori immunoglobulin G antibody was measured by enzyme-linked immunosorbent assay. RESULTS: Of the 3399 participants who did not have organic diseases, 694 (20.4%) had dyspeptic symptoms such as epigastric pain/soreness or postprandial discomfort. Among the 694 participants, atrophic gastritis and positive H. pylori serology were found in 282 (40.6%) and 422 (60.8%), respectively; these proportions were not different from the remaining asymptomatic subjects. Multivariate analysis showed that having relatives with gastric cancer [odds ratio (OR), 1.35; 95% confidence interval (CI), 1.01-1.81], education below college (OR, 1.32; 95% CI, 1.06-1.64), and high-salt diet (OR, 1.33; 95% CI, 1.05-1.68) were associated with FD symptoms. CONCLUSIONS: FD symptoms were frequently found in the health check-up subjects. Relatives of gastric cancer, education below college, and high-salt diet were risk factors of FD, suggesting that FD is a multifactorial disease.

Endoscopic resection for duodenal carcinoid tumors: a multicenter, retrospective study.

BACKGROUND AND AIM: Gastrointestinal carcinoid tumors < 10 mm in diameter and limited to the submucosal layer demonstrate a low frequency of lymph node and distant metastasis, and are suitable for endoscopic treatment. The aim of this study was to assess the efficacy, safety, and long-term prognosis of endoscopic resections for the treatment of duodenal carcinoid tumors. METHODS: This study included a total of 41 duodenal carcinoid tumors in 38 patients between January 2006 and December 2011. The indications for endoscopic resection were lesions ≤ 10 mm in diameter, confined to the submucosal layer, and without lymph node or distant metastasis. Endoscopic resection was accomplished using endoscopic mucosal resection (EMR), EMR with a ligation device (EMR-L), EMR after circumferential precutting, or endoscopic submucosal dissection (ESD). RESULTS: EMR was performed in 18 tumors, EMR-L in 16, EMR after circumferential precutting in 3, and ESD in 4. En-bloc resection was performed in 39 tumors (95%), and endoscopic complete resection was achieved in 40 (98%); pathological complete resection was achieved in 17 tumors (41%). The endoscopic complete resection rate did not differ according to the resection method, but the pathological complete resection rate was higher for ESD than for EMR and EMR-L. Intraprocedural bleeding was noted in five cases, with no occurrence of perforation. Recurrence was not observed during the mean follow-up period of 17 months (range 1-53 months). CONCLUSION: Endoscopic resection appears to be a safe and effective treatment for duodenal carcinoid tumors measuring ≤ 10 mm in diameter and confined to the submucosal layer.

Partial purification and properties of a cysteine protease from citrus red mite Panonychus citri.

Several studies have reported that the citrus red mites Panonychus citri were an important allergen of citrus-cultivating farmers in Jeju Island. The aim of the present study was to purify and assess properties of a cysteine protease from the mites acting as a potentially pathogenic factor to citrus-cultivating farmers. A cysteine protease was purified using column chromatography of Mono Q anion exchanger and Superdex 200 HR gel filtration. It was estimated to be 46 kDa by gel filtration column chromatography and consisted of 2 polypeptides, at least. Cysteine protease inhibitors, such as trans poxy-succinyl-L-leucyl-amido (4-guanidino) butane (E-64) and iodoacetic acid (IAA) totally inhibited the enzyme activities, whereas serine or metalloprotease inhibitors did not affect the activities. In addition, the purified enzyme degraded human IgG, collagen, and fibronectin, but not egg albumin. From these results, the cysteine protease of the mites might be involved in the pathogenesis such as tissue destruction and penetration instead of nutrient digestion.

Prevalence and risk factors of Helicobacter pylori infection in Korea: nationwide multicenter study over 13 years.

BACKGROUND: The aim of this study was to evaluate the time trend of seropositivity of Helicobacter pylori (H. pylori) over the period of 13 years in an asymptomatic Korean population, and investigate associated risk factors. METHODS: This cross-sectional nationwide multicentre study surveyed anti-H. pylori IgG antibodies in 19,272 health check-up subjects (aged [greater than and equal to]16 years) in 2011. Risk factors for H. pylori infection were investigated using logistic regression. Seropositivity in asymptomatic subjects without H. pylori eradication was compared between the years 1998 and 2005. Birth cohort effects were also evaluated. RESULTS: After exclusion of subjects with a history of H. pylori eradication therapy (n = 3,712, 19.3%) and gastric symptoms (n = 4,764, 24.7%), the seroprevalence of H. pylori infection was 54.4% in 10,796 subjects. This was significantly lower than the seroprevalence of 59.6% in 2005 and that of 66.9% in 1998, and this decrease of seropositivity of H. pylori became widespread across all ages and in most areas of the country. This decreasing trend could be explained by cohort analysis. All younger birth cohorts had a lower seroprevalence of H. pylori than older birth cohorts at the same age. Decreased seroprevalence within the same birth cohorts also accounted for this phenomenon. Clinical risk factors of H. pylori infection were higher cholesterol level ([greater than and equal to] 240 mg/dl) (OR = 1.33; 95% CI = 1.14-1.54), male gender, older age, low income, and residence in a rural area. CONCLUSIONS: A decreasing trend of H. pylori seroprevalence due to a birth cohort effect requires further studies on its related human host factors as well as socio-economic and hygienic factors. In addition, the relationship between H. pylori infection and high cholesterol level needs more investigation regarding underlying pathogenesis.

Thirty-year Trend in Inflammatory Bowel Disease on Jeju Island, South Korea.

Background/Aims: Inflammatory bowel disease (IBD), including Crohn's disease (CD) and ulcerative colitis (UC), is increasing in South Korea. On the other hand, there are no reports of the incidence and prevalence of IBD specific to Jeju Island, prompting the necessity of this study. Methods: In this retrospective design, the medical records of 453 patients diagnosed with IBD at Jeju National University Hospital from January 1990 to December 2019 were analyzed. Results: Of the 453 IBD subjects (165 CD, 288 UC) included, the UC: CD ratio was 1.75:1. The incidence of IBD increased continuously from 0.19/105 in 1990 to 6.39/105 in 2017 and after that decreased to 4.92/105 in 2019. The male:female ratio was 2.24:1 for CD and 1.29:1 for UC. In the CD subjects, the disease activity included remission (33.3%), mild (25.5%), moderate (30.9%), and severe (6.1%). In UC subjects, the disease activity included remission (24.0%), mild (35.4%), moderate (28.8%), and severe (6.2%). According to the Montreal classification, the cases were as follows: CD: terminal ileum (22.4%), colon (9.7%), ileocolon (66.1%), and upper gastrointestinal involvement (27.3%), and perianal fistula/abscess was present in 43.6% of subjects before or at diagnosis: UC: proctitis (43.4%), left-sided colitis (29.1%), and pancolitis (23.3%) at diagnosis. Conclusions: The incidence of IBD on Jeju Island has increased steadily for approximately 30 years but has exhibited a decline since 2017. Therefore, the incidence of IBD in Jeju is believed to have plateaued. Further study will be needed for clarification.

Surveillance strategy of atrophic gastritis and intestinal metaplasia in a country with a high prevalence of gastric cancer.

BACKGROUND: It is not clear which screening examinations are best suited for gastric cancer prevention, especially in patients with atrophic gastritis and intestinal metaplasia. Therefore, we investigated the gastric cancer screening methods and intervals that are performed in clinical practice in an area with a high prevalence of gastric cancer. METHODS: Eighty-seven physicians voted by keypad and discussed the consistency of endoscopic diagnosis of atrophic gastritis and intestinal metaplasia at the Annual Symposium of the Korean College of Helicobacter and Upper Gastrointestinal Research. Additionally, 100 core members of this academic society were asked via e-mail to complete the questionnaires related to screening strategies for gastric cancer. RESULTS: The most common recommendation for the subjects with intestinal metaplasia was an annual endoscopic follow-up (95.5% vs. 80.4% in the expert and non-expert groups, respectively; P = 0.118). Annual endoscopic follow-up was also the most predominant recommendation for atrophic gastritis (95.5% vs. 76.5%; P = 0.092), regardless of the physicians' endoscopic experience, position, and degree of the hospital. However, the correct answer rate for the diagnosis of normal endoscopic findings was only 16.7 and 14.1% in the expert and non-expert groups, respectively (P = 0.883). CONCLUSIONS: The most common practical screening strategy for patients with atrophic gastritis and intestinal metaplasia in Korea was annual endoscopic examination. However, a new program estimating individualized gastric cancer risk might be needed because of the low inter-observer agreement in the endoscopic diagnosis of atrophic gastritis and intestinal metaplasia.

Clinical characteristics of an esophageal fish bone foreign body from Chromis notata.

Damselfish Chromis notata is a small fish less than 15 cm long and it is widespread in the Indo-Pacific Ocean. Of all the cases of fish bone foreign body (FBFB) disease at our hospital, a damselfish FBFB was very common, and a specific part of the bone complex was involved in the majority of cases. This study was performed to evaluate the clinical characteristics of damselfish FBFB in Jeju Island. We retrospectively reviewed the medical records from March 2004 to March 2011 for foreign body diseases. Among 126 cases of foreign body diseases, there were 77 (61.1%) cases of FBFB. The mean age ± standard deviation was 57.8 ± 12.7 yr, and this was higher in females 60.9 ± 14.6 yr vs 54.1 ± 8.7 yr. Damselfish was the most common origin of a FBFB 36 out of total 77 cases. The anal fin spine-pterygiophore complex of damselfish was most commonly involved and cause more severe clinical features than other fish bone foreign bodies; deep 2.7 ± 0.8 cm vs 2.3 ± 0.8 cm; P < 0.01, more common mural penetration 23/36 vs 10/41; P < 0.01, and longer hospital stay 12.6 ± 20.0 days 4.7 ± 4.8 days; P = 0.02. We recommend removing the anal fin spine-pterygiophore complex during cleaning the damselfish before cooking.

Gluteal and Presacral Abscess Due to Crohn's Disease with Multiple Fistulas.

The abscess is a common complication of Crohn's disease (CD), with the perianal form more frequent than gluteal or presacral which is relatively rare. There are few case reports of gluteal abscess combined with presacral abscess caused by CD and the treatment has not been established. A 21-year-old male was admitted with right buttock and lower back pain with a duration of 3 months. He had a history of CD in the small intestine diagnosed 10 months previously. He had poor compliance and had not returned for follow-up care during the previous 6 months. Abdominopelvic CT indicated newly developed multiple abscess pockets in right gluteal region, including piriformis muscle and presacral space. Additionally, fistula tracts between small bowel loops and presacral space were observed. Patient's CD was moderate activity (273.12 on the Crohn's Disease Activity Index [CDAI]). Treatment was started with piperacillin/ tazobactam antibiotic but patient developed a fever and abscess extent was aggravated. Therefore, surgical incision and drainage was performed and 4 Penrose drains were inserted. Patient's pain and fever were resolved following surgery. Infliximab was then administered for the remaining fistulas. After the induction regimen, multiple fistula tracts improved and patient went into remission (CDAI was -0.12).

Expression profile of CD98 heavy chain and L-type amino acid transporter 1 and its prognostic significance in colorectal cancer.

L-type amino acid transporter (LAT1) is a neutral amino acid transporter, forming a heterodimer complex with the CD98 heavy chain (CD98hc). In this study, we studied the expression profiles of LAT1 and CD98hc in colorectal cancer (CRC) and its precursor lesions. Transcription levels of CD98hc and LAT1 were significantly increased in CRC compared to the matched normal mucosa. CD98hc and LAT1 expression showed no significant correlations with cancer stem cell markers and intestinal stem cell markers, whereas both had positive correlations with Wnt target genes, AXIN2, and EPHB2, suggesting an association with aberrant Wnt signaling activation. Immunohistochemical analysis revealed that CD98hc and LAT1 are not expressed in normal colonic mucosa and various benign lesions including hyperplastic polyps and sessile and traditional serrated adenomas. CD98hc and LAT1 expressions began to appear in tubular adenomas and further increased in carcinomas. Of interest, CD98hc expression decreased during lymph node metastasis. Survival analysis demonstrated that CD98hc and LAT1 have no significant prognostic effect in CRCs. In conclusion, CD98hc and LAT1 are not normally expressed in colonic mucosa and most benign lesions. Their expression began to appear in tubular adenomas and further increased during the adenoma-to-carcinoma transition. CD98hc expression decreased while metastasizing to regional lymph nodes. However, CD98hc and LAT1 expressions had no prognostic value in patients with CRC.

EPHB2 expression is associated with intestinal phenotype of gastric cancer and indicates better prognosis by suppressing gastric cancer migration.

The protein tyrosine kinase Ephrin type-B receptor 2 (EPHB2) belongs to one of the intestinal stem cell signature genes and plays a crucial role in maintaining the crypt-villous axis. Herein, we aimed to investigate the expression of EPHB2 during gastric carcinogenesis and evaluated its prognostic and functional significance in gastric cancer (GC). EPHB2 expression was upregulated in intestinal metaplasia and GCs compared to normal antral and fundic glands. EPHB2 mRNA levels were strongly correlated with the intestinal stem cell markers OLFM4, LGR5, and EPHB3. Notably, EPHB2 expression was significantly correlated with CDX2 expression, and in vitro studies demonstrated that CDX2 expression increased both EPHB2 transcription and protein levels. In a large cohort of GC patients, EPHB2 positivity was observed in 39% of 704 GCs and was negatively correlated with tumor differentiation, lymphovascular invasion, and tumor-node-metastasis stages. Notably, EPHB2 positivity was associated with better overall survival, and it was an independent prognostic marker in intestinal-type GCs. Overexpression of EPHB2 in GC cell lines, MKN-28 and MKN-74, reduced migration activity by suppressing phosphorylation of focal adhesion kinase, whereas no significant difference was observed in proliferation rates. Thus, we suggest that EPHB2 acts as a tumor suppressor in GCs and can be a prognostic marker in intestinal-type GCs.

Expression profile of intestinal stem cell and cancer stem cell markers in gastric cancers with submucosal invasion.

Cancer stem cells (CSCs) are believed to be responsible for tumor growth, invasion, and metastasis. Submucosal invasion, which greatly enhances metastasis risk, is a critical step in gastric cancer (GC) progression. To identify stem cell-related markers associated with submucosal invasion and lymph node (LN) metastasis in GCs, we investigated the expression of candidate CSC markers (CD133, CD44, and ALDH1A) and intestinal stem cell (ISC) markers (EPHB2, OLFM4, and LGR5) in early GCs that manifested submucosal invasion. We discovered that EPHB2 and LGR5 expression was frequently confined to the basal area of the lamina propria (basal pattern) in mucosal cancer, and the proportion of stem cell marker-positive cells substantially increased during submucosal invasion. CD44 expression showed a focal pattern, ALDH1A was predominantly expressed diffusely, and there was no expansion of CD44 or ALDH1A expression in the submucosal cancer cells. Unexpectedly, no CSC markers showed any associations with LN metastasis, and only loss of EPHB2 expression was associated with increased LN metastasis. Treatment of RSPO2, a niche factor, along with Wnt 3a, to GC cells led to increased EPHB2 and LGR5 mRNA levels. RNA in situ hybridization confirmed specific RSPO2 expression in the smooth muscle cells of the muscularis mucosa, suggesting that RSPO2 is responsible for the increased expression of ISC markers in GC cells at the basal areas. In summary, no stem cell markers were associated with increased LN metastasis in early GCs. Conversely, isolated EPHB2 expression was associated with lower LN metastasis. EPHB2 and LGR5 showed a basal distribution pattern along with enhanced expression in submucosal invading cells in early GCs, which was induced by a niche factor, RSPO2, from the muscularis mucosa.

The Intestinal Stem Cell Marker SMOC2 Is an Independent Prognostic Marker Associated With Better Survival in Gastric Cancer.

BACKGROUND/AIM: SPARC-related modular calcium-binding protein 2 (SMOC2), a secreted matricellular protein, is reported to be involved in cancer progression such as cell cycle, angiogenesis, and invasion. In this study, we aimed to investigate the expression of SMOC2 in various gastric lesions and assessed its prognostic value in a large cohort of gastric cancer (GC) patients. PATIENTS AND METHODS: SMOC2 mRNA levels were measured by quantitative real-time PCR using 26 matched fresh-frozen GC samples. SMOC2 protein expression was determined by immunohistochemistry on tissue microarrays including 734 GC specimens and its correlations with clinicopathological features and survival were evaluated. RESULTS: The transcription level of SMOC2 was higher in GC samples compared to normal mucosa (p=0.006). Its expression levels were associated with the intestinal stem cell (ISC) marker, LGR5, but there were no correlations with EPHB2 and OLFM4 or the candidate cancer stem cell markers CD133 and CD44. SMOC2 expression was significantly increased in the intestinal metaplasia and was further increased in gastric adenomas and early gastric cancers (EGC). In total, 34% of GCs were positive for SMOC2, and SMOC2 positivity was higher in old (p=0.001) and male (p<0.001) patients, and in well-differentiated GC (p<0.001). SMOC2 expression had a negative association with perineural invasion (p<0.001) and tumor stage (p<0.001). In survival analysis, SMOC2-positive GC patients had much better clinical outcomes in overall survival rates (p<0.001) compared to SMOC2-negative GC patients. The prognostic impact of SMOC2 remained significant both in intestinal (p<0.001) and diffuse-type GC (p<0.001). Remarkably, a multivariate analysis demonstrated SMOC2 as an independent prognostic marker [hazard ratio (HR)=0.732, p=0.045] along with venous invasion (p=0.012), tumor stage (p<0.001) and CDX2 (p=0.028). CONCLUSION: Our results suggest that SMOC2 can be a prognostic marker for better clinical outcomes in GC.

Response to adefovir depends on mutation patterns in precore region, basal core promoter and reverse transcriptase, and on-treatment responses in Lamivudine-resistant chronic hepatitis B patients.

OBJECTIVE: In vitro studies showed that mutations in the basal core promoter (BCP) or precore (PC) region restore the replication inefficiency of the lamivudine-resistant mutant. The aim of this study was to clarify the effect of molecular characteristics on the antiviral response to adefovir in patients with lamivudine-resistant chronic hepatitis B (CHB). METHODS: Sixty-six lamivudine-resistant patients who were treated with adefovir monotherapy were studied. Sequences of BCP, PC region and reverse transcriptase were determined before adefovir therapy. In patients with virologic breakthrough, reverse transcriptase sequencing was performed. RESULTS: The cumulative probabilities of virologic response were 23.3, 46, 52.7 and 59.5% at years 1, 2, 3 and 4, respectively. PC mutation, the absence of compensatory mutations (rtL80I/V or rtV173L), and a decrease in serum hepatitis B virus (HBV) DNA by 3 log or greater at 6 months were independent predictors of virologic response. The cumulative probabilities of virologic breakthrough were 0, 12.9, 30.7 and 44.5% at years 1, 2, 3 and 4, respectively. BCP mutation and a less than 3 log decrease in serum HBV DNA at 6 months were 2 independent risk factors for virologic breakthrough. CONCLUSION: Response to adefovir depends on mutation patterns in the BCP, PC region and reverse transcriptase, and on-treatment decreases in serum HBV DNA in lamivudine-resistant CHB patients.

SMOC2, an intestinal stem cell marker, is an independent prognostic marker associated with better survival in colorectal cancers.

We aimed to investigate the expression profile of SPARC-related modular calcium-binding protein 2 (SMOC2) during colorectal cancer (CRC) progression and assess its prognostic impact in CRC patients. In our study, we showed that SMOC2 transcript level was higher in CRC samples than in normal mucosa (P = 0.017); this level was not associated with candidate cancer stem cell markers (CD44, CD166, CD133, and CD24) or intestinal stem cell markers (LGR5, ASCL2, and EPHB2) except for OLFM4 (P = 0.04). Immunohistochemical analysis showed that SMOC2-positive cells were confined to the crypt bases in the normal intestinal mucosa, hyperplastic polyps, and sessile serrated adenomas, whereas traditional serrated adenomas and conventional adenomas exhibited focal or diffuse distribution patterns. In total, 28% of 591 CRCs were positive for SMOC2, but SMOC2 positivity had negative correlations with lymphatic invasion (P = 0.002), venous invasion (P = 0.002), and tumor stage (P < 0.001). However, a positive association with nuclear ß-catenin expression was seen. Furthermore, while upregulated SMOC2 expression was maintained during the adenoma-carcinoma transition, it decreased in cancer cells at the invasive front but did not decline further during lymph node metastasis. SMOC2 positivity showed no correlations with molecular abnormalities, including microsatellite instability, CpG island methylator phenotype, and mutations of KRAS and BRAF. In addition, we showed comprehensively that SMOC2 positivity is an independent prognostic marker for better clinical outcomes in a large cohort of CRC patients (P = 0.006). In vitro studies also demonstrated that induced SMOC2 expression in DLD1 cells exerts a suppressive role in tumor growth as well as in migration, colony, and sphere formation abilities. Taken together, our results suggest SMOC2 as a candidate tumor suppressor in CRC progression.