Prevalence and Clinical Characteristics of Heterozygous RNF213 p.Arg4810Lys Variant Carriers Diagnosed With Chronic Thromboembolic Pulmonary Hypertension.

BACKGROUND: Ring finger protein 213 (RNF213) p.Arg4810Lys is a susceptibility gene for moyamoya disease, peripheral pulmonary artery stenosis (PPS), and other vascular diseases and thrombosis. We investigated the prevalence and clinical characteristics of RNF213 variant carriers diagnosed with chronic thromboembolic pulmonary hypertension (CTEPH). METHODS AND RESULTS: We retrospectively analyzed the prevalence of the RNF213 p.Arg4810Lys variant in patients diagnosed with CTEPH (n=112) and PPS (n=10). Clinical and angiographic characteristics were evaluated between RNF213 variant carriers diagnosed with CTEPH and noncarriers with CTEPH and homozygous variant carriers with PPS. Eight heterozygous RNF213 p.Arg4810Lys variant carriers (7.1%) were identified among patients diagnosed with CTEPH, while 5 patients with PPS (50%) carried the homozygous variant. The clinical characteristics of heterozygous variant carriers with CTEPH were not remarkably different from those of noncarriers with CTEPH. All heterozygous variant carriers with CTEPH showed webs/bands lesions at the segmental/subsegmental level, with 75% showing distal tortuous vessels. None of the heterozygous variant carriers with CTEPH exhibited the string-of-beads pattern or elongated stenosis. Homozygous variant carriers with PPS showed the string-of-beads pattern, elongated stenosis, and distal tortuous vessels without webs/bands lesions. CONCLUSIONS: A subset of patients diagnosed with CTEPH (7.1%) carried the heterozygous RNF213 p.Arg4810Lys variant. Clinical and angiographic characteristics of heterozygous variant carriers were not remarkably different from those of noncarriers of CTEPH. However, both heterozygous variant carriers with CTEPH and homozygous variant carriers with PPS showed tortuous vessels on angiography.

Risk stratification of synchronous gastric cancers including alcohol-related genetic polymorphisms.

BACKGROUND AND AIM: We previously identified that ever-smoking and severe gastric atrophy in pepsinogen are risk factors for synchronous gastric cancers (SGCs). This study aimed to determine the association of alcohol drinking status or alcohol-related genetic polymorphism with SGCs and also stratify their risk. METHODS: This multi-center prospective cohort study included patients who underwent endoscopic submucosal dissection for the initial early gastric cancers at 22 institutions in Japan. We evaluated the association of alcohol drinking status or alcohol dehydrogenase 1B (ADH1B) and acetaldehyde dehydrogenase 2 (ALDH2) genotypes with SGCs. We then stratified the risk of SGCs by combining prespecified two factors and risk factors identified in this study. RESULTS: Among 802 patients, 130 had SGCs. Both the ADH1B Arg and ALDH2 Lys alleles demonstrated a significant association with SGCs on multivariate analysis (odds ratio, 1.77), although alcohol drinking status showed no association. The rates of SGCs in 0-3 risk factors in the combined evaluation of three risk factors (ever-smoking, severe gastric atrophy in pepsinogen, and both the ADH1B Arg and ALDH2 Lys alleles) were 7.6%, 15.0%, 22.0%, and 32.1%, respectively. The risk significantly increased from 0 to 3 risk factors on multivariate analysis (P for trend <0.001). CONCLUSIONS: Both the ADH1B Arg and ALDH2 Lys alleles were at high risk for SGCs. The risk stratification by these three factors may be a less invasive and promising tool for predicting their risk.

Systemic AA Amyloidosis Secondary to Metastatic Renal Cell Carcinoma in a Hemodialysis Patient with Intractable Diarrhea.

We describe an autopsied case of systemic AA amyloidosis secondary to metastatic renal cell carcinoma presenting intractable diarrhea. Severe diarrhea was the major symptom for the diagnosis of AA amyloidosis. No renal symptoms which are common in AA amyloidosis secondary to renal cell carcinoma were shown because hemodialysis following bilateral nephrectomy had already been started 9 years before. Treatment against metastatic tumors as a solution of AA amyloidosis could not be performed because of bad performance status and the patient died 5 months after the diagnosis. Autopsy findings revealed that AA amyloid deposition was seen in multi-organs including the intestine. The metastatic tumors were histologically compatible as metastasis of renal cell carcinoma. There was no other cause of chronic inflammation such as inflammatory arthritis. We concluded that chronic inflammation provoked by the metastatic tumors of renal cell carcinoma was a major cause of systemic AA amyloidosis. Intestinal AA amyloidosis with malabsorption was the cause of death. Clinicians should keep it in mind that solid organ malignancy can be a cause of AA amyloidosis and renal cell carcinoma is the most common carcinomatous cause. This case is particularly instructive in that progression of amyloidosis may be missed in hemodialysis patients with anuria and that gastrointestinal symptoms can be the primary indicators of systemic amyloidosis. Endoscopic examination including biopsy is important for the diagnosis and early treatment of amyloidosis.

Smoking history and severe atrophic gastritis assessed by pepsinogen are risk factors for the prevalence of synchronous gastric cancers in patients with gastric endoscopic submucosal dissection: a multicenter prospective cohort study.

BACKGROUND: No studies have evaluated the relationship between lifestyle and synchronous gastric cancers (SGCs) in patients with endoscopic submucosal dissection (ESD) for early gastric cancers (EGCs). Using data from the Tohoku gastrointestinal (GI) study, we aimed to identify factors associated with SGCs. METHODS: Tohoku GI study is a multicenter prospective cohort study investigating the relationship between lifestyle and metachronous gastric cancers. Patients who had a schedule to undergo ESD for primary EGCs were enrolled. We used logistic regression analysis to examine the relationship of 15 candidate factors, including lifestyle, with the prevalence of SGCs in this study. RESULTS: Of 850 patients between 2016 and 2019, 16.0% (136 patients) had SGCs. In multivariate analysis, smoking history (odds ratio [OR], 1.93; p = 0.048) and severe atrophic gastritis assessed by pepsinogen (OR, 1.92; p = 0.004) were risk factors for the prevalence of SGCs. Regarding smoking, current smoking (OR, 2.33; p = 0.021), but not former smoking (OR, 1.76; p = 0.098), was a significant risk factor for its prevalence. In the stratified analysis, severe atrophic gastritis assessed by pepsinogen was a risk factor in patients without Helicobacter pylori (H. pylori) eradication (OR, 2.10; p = 0.002), but not a risk factor in those with H. pylori eradication (OR, 0.75; p = 0.737). CONCLUSION: Smoking history was a risk factor for the prevalence of SGCs in patients with ESD for EGCs, and severe atrophic gastritis assessed by pepsinogen was also a risk factor when H. pylori was not eradicated.

Spontaneous reactivation of hepatitis B virus with S gene mutations in an elderly patient with diabetic nephropathy.

Generally, reactivation of hepatitis B virus (HBV) infection is induced by the administration of immunosuppressants or anticancer agents, but reactivation without such drugs has rarely been reported. Here we report an elder case with spontaneous reactivation of HBV replication accompanied by hepatitis B surface antigen (HBsAg) mutations. A 69-year-old man with a history of diabetes mellitus and chronic kidney disease (CKD) was found to be positive for HBsAg (0.072 IU/ml) in June 2018. In May 2019, marked hepatic dysfunction and increased HBsAg (2533.2 IU/ml) were observed when he visited the hospital due to diarrhea and worsening of CKD. At that time, hepatitis B surface antibody (HBsAb) was positive (268.9 mIU/ml) and HBV DNA was 6.0 log IU/ml. After treatment with entecavir, HBV DNA and HBsAg rapidly decreased. Full-genome HBV sequence analysis revealed that the patient was infected with HBV of subgenotype B1 and it had an "a" determinant mutation M133L in the S gene coding HBsAg. Notably, both HBsAg and HBsAb were positive at the time of HBV reactivation, suggesting that the HBV with these mutations escaped from neutralization by HBsAb. This case suggests that immune escape mutations could play an important role in spontaneous HBV reactivation.

Endoscopic Findings of Esophageal Adenosquamous Carcinoma Diagnosed by Endoscopic Mucosal Resection.

Adenosquamous carcinoma (ASC) is a rare histological type of esophageal carcinoma. Esophagogastroduodenoscopy for the health checkup of a 71-year-old male revealed the presence of a slightly elevated lesion like a submucosal tumor at the lower part of the esophagus. The center of it was slightly depressed, and the depressed area was not stained by iodine. Magnifying endoscopy with narrow-band imaging revealed reticular pattern vessels in the depressed area, whereas no irregularity of the microvascular pattern of the surrounding area was evident. One of the biopsied specimens taken from the depressed area was diagnosed as squamous intraepithelial neoplasia, but a malignant tumor with submucosal invasion was suspected based on the findings of endoscopic ultrasonography. Endoscopic mucosal resection using a cap-fitted endoscope was performed, and the lesion was diagnosed as esophageal ASC histologically. Carcinomas that formed nested and ductal structures existed in the lamina propria and invaded to the submucosa. Almost all of them were covered by non-invasive intraepithelial neoplasia, whereas small erosion was seen in the central depressed area. The growing pattern of ASC was quite different from that of typical differentiated squamous cell carcinomas. When we do endoscopic examination for an esophageal lesion like submucosal tumor, we have to consider the possibility of an esophageal carcinoma that has a similar growing pattern. If reticular pattern vessels are seen with magnifying endoscopy, the existence of an invasive carcinoma is suspected, and additional endoscopic ultrasonography is recommended. Possible efforts to gain histological findings have to be made using bowling biopsy, endoscopic resection, and so on.

The Risk Factors for Metastasis in Non-Ampullary Duodenal Neuroendocrine Tumors Measuring 20 mm or Less in Diameter.

BACKGROUND/AIMS: The treatment strategy for non-ampullary duodenal neuroendocrine tumors (NAD-NETs) ≤20 mm in diameter has not been established. In this study, we aimed to evaluate the detailed characteristics of NAD-NETs ≤20 mm in diameter to clarify the risk factors of subsequent metastasis. METHODS: The patients with NAD-NETs ≤20 mm in diameter who had been treated at 12 institutions between 1992 and 2013 were enrolled. Clinical records were retrieved, and histopathological findings of all cases were centrally reviewed by 2 pathologists. RESULTS: We studied 49 patients with a mean follow-up period of 66.5 months. Thirty-five patients were initially treated with endoscopic resection (ER), and 14 with surgery. A univariate analysis revealed the ORs and 95% CIs of the risk factors for metastasis were lymphovascular invasion (12.5 [2.01-77.9]), multiple tumors (9.75 [1.46-65.4]), a tumor size of 11-20 mm (6.67 [1.21-36.6]), and World Health Organization grade G2 (7.13 [1.16-43.9]). Five-year overall and disease-specific survival rates were 86.1 and 97.2%, respectively. CONCLUSION: This is the first study to demonstrate the risk factors of metastasis in NAD-NETs ≤20 mm in diameter. These findings may be helpful for determining the appropriate therapeutic approach and the clinical strategy of treatment following ER.

Suppressive expression of CD274 increases tumorigenesis and cancer stem cell phenotypes in cholangiocarcinoma.

Cholangiocarcinoma is an aggressive malignant tumor originating from intrahepatic or extrahepatic bile ducts. Its malignant phenotypes may be assumed by cancer stem cells (CSC). Here, we demonstrate that CD274 (PD-L1), known as an immunomodulatory ligand, has suppressive effects on CSC-related phenotypes of cholangiocarcinoma. Using two human cholangiocarcinoma cell lines, RBE and HuCCT1, we attempted to isolate the CD274(low) and CD274(high) cells from each cell line, and xenografted them into immunodeficient NOD/scid/γcnull (NOG) mice. We found that the CD274(low) cells isolated from both RBE and HuCCT1 are highly tumorigenic in NOG mice compared with CD274(high) cells. Furthermore, the CD274(low) cells possess several CSC-related characteristics, such as high aldehyde dehydrogenase (ALDH) activity, reduced reactive oxygen species production and a dormant state in the cell cycle. Furthermore, depletion of CD274 expression by shRNA in RBE cells enhances their tumorigenicity and increases ALDH activity. These findings are compatible with our observation that clinical cholangiocarcinoma specimens are classified into low and high groups for CD274 expression, and the CD274 low group shows poorer prognosis when compared with the CD274 high group. These results strongly suggest that CD274 has a novel function in the negative regulation of CSC-related phenotypes in human cholangiocarcinoma, which is distinct from its immunomodulatory actions.

Comparison of the long-term outcomes of endoscopic resection for superficial squamous cell carcinoma and adenocarcinoma of the esophagus in Japan.

OBJECTIVES: Few studies have simultaneously evaluated the long-term outcomes of endoscopic resection (ER) for squamous cell carcinoma (SCC) and adenocarcinoma (AC) of the esophagus in Japan. The objective of this study was to evaluate the long-term outcomes of ER for superficial esophageal cancer in consecutive patients. METHODS: This was a retrospective study from a single institution. From April 2001 to June 2012, 204 patients with SCC and 26 patients with AC were included from a total of 355 consecutive patients who were treated by esophageal ER at the Tohoku University Hospital. Patients with submucosal invasion deeper than 200 µm and lymphovascular involvement were excluded. The intervention followed was endoscopic therapy. RESULTS: Overall survival, disease-free survival, and recurrence rates were evaluated as long-term outcomes. In the SCC group, during the median observation time of 36.5 months (range, 6-120 months), 22 (10.8%) patients experienced metachronous recurrence, 4 (2.0%) patients experienced local recurrence, and 27 (13.2%) patients died from causes unrelated to SCC. In the AC group, during the median observation time of 45.5 months (range, 6-131 months), one patient (3.8%) experienced metachronous recurrence and two (7.7%) died from causes unrelated to AC. The cumulative 5-year overall survival rates were not significantly different between SCC (75.9%) and AC (88.9%) (P=0.120). The cumulative 5-year disease-free survival rates of SCC (57.1%) were significantly lower than those of AC (85.2%; P=0.017). The cumulative 5-year recurrence rates of SCC (32.0%) were significantly higher than those of AC (4.2%; P=0.023). CONCLUSIONS: The rate of recurrence after ER was higher in patients with SCC than that in patients with AC. These findings suggest that, by detecting AC of the esophagus earlier, a satisfactory prognosis without recurrence can be expected after ER in Japan, and more rigorous endoscopic follow-up is necessary after ER in patients with SCC than in those with AC.

Endoscopically proven case of rapid esophagogastric variceal progression and rupture as a result of portal hypertension with liver sarcoidosis.

Sarcoidosis is a multi-systemic disease of unknown etiology that results in the development of non-caseating epithelioid granulomas. The liver is the third most frequently involved organ after the lymph nodes and the lungs. Most cases of liver sarcoidosis do not present with symptoms and involve minimal liver dysfunction, but some cases display progression to portal hypertension and liver cirrhosis, and finally to liver failure. The mechanism and the risk of progression in liver sarcoidosis are still unknown because of the diagnostic difficulty associated with this condition, and because follow-up examinations can only be done in an invasive manner. Here, we present an informative case of liver sarcoidosis with rapid progression of esophagogastric varices. Four months prior to the definitive diagnosis, no signs of varices were observed on endoscopy, and developmentof esophagogastric varices, rapid progression, and eventual rupture occurred in a short period of time. A liver biopsy, carried out after endoscopic sclerotherapy, revealed that granulomas primarily affected the portal area without fibrotic and cirrhotic changes, which is considered a primary cause of portal hypertension and esophagogastric varices. Following the liver biopsy, the patient was given systemic steroids and is currently receiving outpatient care. Thus, we should consider the possibility that liver sarcoidosis, even in the absence of cirrhotic changes, can cause serious events such as esophagogastric variceal rupture following rapid progression as a result of portal hypertension.

Enhanced expression of long non-coding RNA HOTAIR is associated with the development of gastric cancer.

The long non-coding RNA HOTAIR has been reported to be a poor prognostic biomarker in a variety of malignant tumors. However, little is known about the association of HOTAIR with gastric cancer. We examined the expression of HOTAIR in 68 gastric cancer samples using quantitative real-time RT-PCR and analyzed its correlation with the clinical parameters. The functional role of HOTAIR was examined by generating human gastric cancer cell lines with increased or suppressed HOTAIR expression. The anchorage -independent growth was assessed by soft agar assay. The increased or suppressed HOTAIR expressing gastric cancer cells were injected into the tail vein or peritoneal cavity of immunodeficient mice to examine the effect of this molecule on metastasis and peritoneal dissemination. The expression of HOTAIR was significantly higher in cancer lesions than in adjacent non-cancerous tissues in human gastric cancers. In the diffuse type of gastric cancer, the High-HOTAIR group (HOTAIR/GAPDH > 1) showed significantly more venous invasion, frequent lymph node metastases and a lower overall survival rate compared to the Low-HOTAIR group (HOTAIR/GAPDH < 1). Colony formation on the soft agar was enhanced in a HOTAIR-dependent manner. HOTAIR-expressing MKN74 formed more liver metastasis compared to control when they were injected into the tail vein of mice. In addition, reduced expression of HOTAIR in KATO III suppressed peritoneal dissemination. These results suggest that HOTAIR plays a pivotal role in the development of gastric cancer.

Large noncoding RNA HOTAIR enhances aggressive biological behavior and is associated with short disease-free survival in human non-small cell lung cancer.

HOTAIR is one of long non-coding RNAs and its expression correlates with the prognosis and metastasis in various cancers. We showed that HOTAIR expression has an important role in the development of non-small cell lung cancer (NSCLC). In this study, we examined the expression of HOTAIR in 77 NSCLCs, their corresponding normal lung tissues and 6 brain metastases by quantitative real-time RT-PCR. High expression of HOTAIR (tumor/normal ratio ⩾2) was detected in 17 patients (22.1%) and was frequently found in patients with advanced stage, lymph node metastasis or lymph-vascular invasion and short disease free interval. Furthermore, brain metastases show significantly higher HOTAIR expression compared to primary cancer tissues. HOTAIR-expressing A549 cells showed induced cell migration and anchorage-independent cell growth in vitro. These results indicate the expression of HOTAIR enhanced the aggressive behavior of NSCLC cells.

Barrett's esophageal cancer in which magnifying narrow-band imaging was useful for diagnosing extension under the squamous epithelium.

A 36-year-old man complained of heartburn. Gastrointestinal endoscopies showed a reddish and slightly depressed lesion in the right-anterior wall of the esophagogastric junction. With white light imaging, the area of the adenocarcinoma under the squamous epithelium was difficult to detect, but a slightly flat, elevated lesion appeared in the area of adenocarcinoma under the squamous epithelium. With narrow-band imaging (NBI) in the area of the Barrett's esophageal cancer under the squamous epithelium, a slight, brownish change could be observed. In addition, with the magnifying technique, irregular mesh-like vessels were observed, suggesting the presence of differentiated adenocarcinoma under the squamous epithelium. The lesion was resected en bloc by endoscopic submucosal dissection, and Barrett's esophageal cancer under the squamous epithelium was histologically confirmed. In this case, NBI with magnifying endoscopy was very useful to diagnose the extension of Barrett's esophageal cancer under the squamous epithelium.

Gender differences in oesophageal mucosal injury in a reflux oesophagitis model of rats.

OBJECTIVE: There is a strong male predominance of oesophageal adenocarcinoma, which might be related to the higher prevalence of precursor lesions such as erosive reflux oesophagitis in men compared with women. This experiment investigated the gender difference in a reflux oesophagitis model of rats and explored the potential role of oestrogen in controlling oesophageal tissue damage. DESIGN: An acid-reflux oesophagitis model was surgically produced in male and female rats, and ascorbic acid in the diet and sodium nitrite in the drinking water were administered to half of either group to provoke luminal exogenous nitric oxide (NO) as an exacerbating agent. Seven days after the surgery, the oesophagus was excised, and the injury area, myeloperoxidase activity and pro-inflammatory cytokine levels were measured. Furthermore, 17ß-oestradiol was administered to ovariectomised female rats or male rats, which then underwent reflux oesophagitis surgery. RESULTS: While there was no gender difference in oesophageal damage in the baseline model, oesophageal damage was more intensively observed in males than in females in the presence of exogenous NO administration. While oesophageal damage was increased in ovariectomised rats compared with sham ovariectomised, exacerbated oesophageal damage was attenuated by the replacement of 17ß-oestradiol. In addition, exacerbated oesophageal damage in male rats was suppressed by 17ß-oestradiol. CONCLUSION: This is the first study showing the prominent gender difference in the severity of oesophageal tissue damage in a gastro-oesophageal reflux disease-related animal model, highlighting the critical involvement of oestrogen in controlling gastro-oesophageal reflux disease-related oesophageal epithelial injury.

The role of nitric oxide in the induction of caudal-type homeobox 2 through epidermal growth factor receptor in the development of Barrett's esophagus.

OBJECTIVE: The high concentration of nitric oxide (NO) around the gastro-esophageal junction (GEJ) might play an important role in the development of Barrett's esophagus (BE), a precursor of Barrett's adenocarcimona. Although previous studies revealed that the expression of caudal-type homeobox 2 (CDX2), an important marker of BE, might be induced through Epidermal Growth Factor Receptor (EGFR), the roles of NO in this signal transduction remain unclear. MATERIAL AND METHODS: First, we investigated the expressions of EGFR, CDX2 and nitrotyrosine by immunohistochemical study for BE and squamous epithelium of human specimens. Second, we studied the effect of peroxynitrite, peroxynitrite stimulator, SIN-1, or NO donor, NOC7, on the expression of phosphorylated EGFR and CDX2 in KYSE30, an EGFR-rich human esophageal squamous cell carcinoma cell-line. Specific inhibitors for EGFR, AG1478 and small interfering RNA for EGFR (EGFR-siRNA) were employed to elucidate the role of EGFR in the induction of CDX2. RESULTS: The immunohistochemical study revealed that the expressions of EGFR, CDX2 and nitrotyrosine in BE were stronger than those in squamous epithelium with positive correlations. Exposure to peroxynitrite, SIN-1 or NOC7 induced EGFR phosphorylation and CDX2 expression in dose- and time-dependent manners. Both EGFR phosphorylation and CDX2 induction were significantly diminished by AG 1478 and EGFR-siRNA. CONCLUSIONS: We revealed for the first time that extrinsic NO might directly induce CDX2 expression through EGFR phosphorylation. We suggested that NO had an important role in the development of BE from squamous epithelium around GEJ.

Gastric cancers emerging after H. pylori eradication arise exclusively from non-acid-secreting areas.

Although Helicobacter pylori (H. pylori) eradication has some inhibitory effects on the subsequent development of gastric cancer, there are sporadic cases of gastric cancer even after successful eradication. The pathogenesis of gastric cancer emerging after H. pylori eradication remains to be clarified. In this study, employing Congo-red chromoendoscopy, which is capable of visualizing the acid-secreting fundic mucosa, we investigated the topographic relationship of the acid secretion pattern to the occurrence site of gastric cancers emerging after eradication. Fourteen consecutive patients who suffered from new gastric cancer after eradication, defined as lesions that were discovered at least 2 years after the eradication, were prospectively enrolled. Whether the neoplasias arose from acid-secreting or non-acid-secreting areas was evaluated with Congo-red chromoendoscopy. Biopsy specimens taken from the two areas were subjected to histologic evaluation and immunohistochemistry for Ki-67 and p53. The mean period from the eradication to the subsequent occurrence of gastric cancer was 74 (44) months. There were two cancer lesions in 5 cases, and thus there was a total 19 lesions from 14 cases. Congo-red chromoendoscopy revealed that all 19 lesions arose exclusively from non-acid-secreting areas. Histological examination revealed sustained hyperproliferation and accumulation of p53 protein was frequently detectable in non-acid-secreting areas. Genetic alteration such as p53 mutation seems to be already present in the residual non-acid-secreting areas after eradication, areas that could be the origin of gastric carcinogenesis after eradication. Identification of such high-risk areas should be a promising approach for estimating the individual cancer risk after eradication.

Signet Ring Cell Gastric Cancer Occurring after Radiation Therapy for Helicobacter pylori-Uninfected Mucosa-Associated Lymphoid Tissue Lymphoma.

Helicobacter pylori infection is the major cause for mucosa-associated lymphoid tissue (MALT) lymphoma and gastric cancers. On the other hand, gastric cancers are known to arise from gastric mucosal atrophy. We here report a case of signet ring cell gastric cancer that developed after radiation therapy for MALT lymphoma in H. pylori-uninfected patient whose stomach did not show gastric mucosal atrophy. A 58-year-old female was referred to our hospital for treatment of gastric MALT lymphoma. This patient was not infected with H. pylori, and upper gastrointestinal endoscopy revealed that she did not have gastric mucosal atrophy but had submucosal tumor-like MALT lymphoma lesion in the anterior wall of the upper gastric body. Since conventional eradication therapy was ineffective, her whole stomach was irradiated as a second-line therapy. The MALT lymphoma lesion turned into complete remission state after the therapy. The patient was followed every 6 months by upper gastrointestinal endoscopy for 4 years as complete remission until a newly developed decolorized depressed lesion was detected in the greater curvature of the proximal antrum, a completely different location from the MALT lymphoma lesion. A biopsy specimen from the lesion contained signet ring cell carcinoma, and she was successfully treated by endoscopic submucosal dissection. No signs of recurrence have been detected so far. The radiation therapy for MALT lymphoma might be associated with the occurrence of this signet ring cell gastric cancer, and since MALT lymphoma is indolent in nature, this case suggests that careful consideration is required when choosing the second-line therapy for MALT lymphoma patients.

Exogenous luminal nitric oxide exposure accelerates columnar transformation of rat esophagus.

Exposure of the esophageal mucosa to refluxed gastroduodenal contents is recognized to be an important risk factor for Barrett's esophagus (BE). At the human gastroesophageal junction, nitric oxide is generated luminally through the enterosalivary recirculation of dietary nitrate, and in cases with gastroesophageal reflux, the site of luminal nitric oxide generation could shift to the distal esophagus. The aim of this study is to investigate whether exogenous luminal nitric oxide could promote the development of BE in rats. Sodium nitrite plus ascorbic acid were administered to a rat surgical model of BE, in which the gastroduodenal contents were refluxed into the esophagus to generate exogenous luminal nitric oxide in the esophagus by the acid-catalyzed chemical reaction between the 2 reagents. The emergence of BE was evaluated histologically in the early phase (several weeks) after the surgery with or without exogenous nitric oxide administration. To elucidate the histogenesis of BE, CDX2, MUC2 and MUC6 expressions were investigated immunohistochemically. Coadministration of sodium nitrite plus ascorbic acid significantly accelerated the timing of emergence and increased the area of BE compared with controls. Administration of either reagent alone did not show any promotive effects on BE formation. Immunohistochemically, the columnar epithelium thus induced was similar to the specialized intestinal metaplasia in human BE. The results of this animal model study suggest that exogenous luminal nitric oxide could be involved in the pathogenesis of the columnar transformation of the esophagus. Further studies in human are warranted.