Clinical significance of circulating biomarkers of immune-checkpoint molecules with atezolizumab plus bevacizumab therapy in unresectable hepatocellular carcinoma.

BACKGROUND: The aims of this study were to identify clinically significant biomarkers of a response to atezolizumab plus bevacizumab (ATZ + BV) therapy and to develop target strategies against unresectable hepatocellular carcinoma (u-HCC). METHOD: We first investigated the potential of circulating tumor DNA (ctDNA) to serve as a biomarker for predicting the therapeutic outcome in 24 u-HCC patients treated with ATZ + BV therapy. Next, we analyzed levels of immune-related cytokines in blood samples from 134 u-HCC patients who received ATZ + BV. For this, serum immune-related molecules or cancer-immune cycle-related molecules that have been reported in HCC patient sera, namely CD274, LAG-3, CCL2, 4, 5, CXCL1, 9, 10, 12, 13, CX3CL1, CCR5, IFNγ and IL-6, 8 were measured using enzyme-linked immunosorbent assay. RESULTS: More than 1% of variant read frequency (VRF) mutations were found in TP53, APC, PIK3CA and VHL, although with no correlation with treatment response. Among the 15 cytokines evaluated, CXCL9 and LAG-3 levels were significantly different between patients with objective response (OR), stable disease (SD), and progressive disease (PD) following ATZ + BV treatment. Receiver-operating characteristic curve analyses of CXCL9 (cut-off value: 419.1 pg/ml) and LAG-3 (cut-off value: 3736.3 pg/ml) indicated areas of 0.779 and 0.697, respectively, for differentiating PD from non-PD and OR from non-OR. In multivariate analysis of progression-free survival (PFS) and overall survival (OS), high serum CXCL9 (hazard ratio (HR) and 95% confidence interval (CI): 0.412 (0.251-0.677) (p = 0.0005) for PFS and 0.252 (0.125-0.508) (p = 0.0001) for OS), and low serum LAG-3 (HR and 95% CI 0.419 (0.249-0.705) (p = 0.0011) for PFS and 0.294 (0.140-0.617) (p = 0.0012) for OS) were independent positive predictive factors. CONCLUSION: Although, as far as we examined, no ctDNA mutations in blood were found to be related to ATZ + BV treatment efficacy, serum CXCL9 and LAG-3 levels, which are related to the cancer-immune cycle, were associated with treatment efficacy and could be predictive markers of the efficacy of ATZ + BV treatment in HCC patients.

Larotrectinib efficacy for liver metastases in papillary thyroid carcinoma patient harboring SQSTM1-NTRK1 fusion.

BACKGROUND: Pooled data analysis from three phase I/II larotrectinib clinical trials revealed that larotrectinib demonstrated rapid and durable disease control and a favorable safety profile for patients with neurotrophic-tropomyosin receptor kinase (NTRK) fusion positive thyroid carcinoma. Herein, we report the case of a patient with papillary thyroid carcinoma (PTC) and liver metastases who demonstrated a durable response to treatment with larotrectinib. CASE PRESENTATION: A 50-year-old female with PTC was referred to our hospital for postoperative observation. Computed tomography (CT) scan was performed to screen for distant metastasis, since thyroglobulin concentration increased gradually, and revealed multiple distant metastases, including multiple liver metastases. Radioactive iodine was administered at a dose of 100 mCi. However, uptake was observed only in the thyroid bed, and distant metastases had no avidity. As liver metastases progressed, lenvatinib (24 mg/day) was initiated after confirmation of liver metastases by liver biopsy 9 years and 1 month after the initial referral to our hospital. Since the multiple metastases became refractory for lenvatinib, the OncoGuide™ NCC Oncopanel System was performed, and the SQSTM1-NTRK1 gene fusion was confirmed. Larotrectinib was subsequently administered at a dose of 200 mg/day. The CT before the initiation of larotrectinib showed multiple liver metastases with a maximum diameter of 48 mm. The first CT evaluation at 1 month after the initiation of larotrectinib treatment showed that the tumor volume was reduced by 28% in the RECIST 1.1 criteria. After 3 months of larotrectinib treatment, a 38% reduction in the tumor volume was achieved as the best clinical response. The only side effect was grade 1 myalgia. At 12 months after the initiation of larotrectinib treatment, none of the lesions had progressed. CONCLUSIONS: In conclusion, larotrectinib demonstrated effective antitumor activity against liver metastases of PTC, a relatively rare site of distant metastasis. Furthermore, the efficacy of larotrectinib was maintained, even though the patient had a history of multi-tyrosine kinase inhibitor treatment and a relatively infrequent fusion gene, SQSTM1-NTRK1.

Activation of STING in pancreatic cancer-associated fibroblasts exerts an antitumor effect by enhancing tumor immunity.

Pancreatic ductal adenocarcinoma (PDAC) has a high mortality rate; therefore, the development of effective treatments is a priority. The stimulator of interferon genes (STING) pathway enhances tumor immunity by inducing the production of type 1 interferon (IFN) and proinflammatory cytokines and chemokines and promoting the infiltration of cytotoxic T cells. To assess the function of STING on pancreatic tumorigenesis, Ptf1aER-Cre/+ LSL-KrasG12D/+ p53loxP/loxP mice (KPC mice) and Ptf1aER-Cre/+ LSL-KrasG12D/+ p53loxP/loxP/STING-/- mice (KPCS mice) were generated. However, STING deletion did not affect pancreatic tumorigenesis in mice. Because STING is expressed not only in immune cells but also in cancer-associated fibroblasts (CAFs), we evaluated the STING function in PDAC CAFs. A mouse STING agonist 5,6-Dimethyl-9-oxo-9H-xanthene-4-acetic acid (DMXAA) was administered to KPC mice and CAFs from KPC mice and the resulting immune response was evaluated. DMXAA activated STING in PDAC CAFs in KPC mice, promoting cytotoxic T cell infiltration by secreting proinflammatory cytokines and enhancing tumor immunity. We next generated STING-deficient PDAC cells and subcutaneous tumors in which STING was expressed only in CAFs by performing bone marrow transplantation and assessed the antitumor effect of STING-activated CAFs. The administration of DMXAA to subcutaneous tumors expressing STING only in CAFs sustained the antitumor effect of DMXAA. About half of human PDACs lacked STING expression in the cancer stroma, suggesting that STING activation in PDAC CAFs exerts an antitumor effect, and STING agonists can be more effective in tumors with high than in those with low STING expression in the stroma.

Genetic landscape of 482 thyroid carcinomas: analysis with the national datacenter for cancer genomic medicine in Japan.

PURPOSE: Comprehensive genomic profiling is useful for patients with Thyroid carcinoma (TC) for whom standard treatment has become refractory. We analyzed the clinical and genomic characteristics of patients with TC using the Japanese nationwide Center for Cancer Genomics and Advanced Therapeutics (C-CAT) database. METHODS: This retrospective observational study used the data obtained from the C-CAT database. Genomic information has been accumulated on representative gene mutations associated with TC. RESULTS: Among the 482 patients, 212 (44%) were male and 270 (56%) were female. According to histological type, 259 (54%), 46 (10%), 16 (3%), 51 (11%), and 110 (23%) patients had papillary TC (PTC), follicular TC, medullary TC, poorly differentiated TC, and anaplastic TC (ATC), respectively. Among the genomic profiling tests, FoundationOne CDx (n = 388; 80%) was the most frequently performed. The frequencies of BRAF, NRAS, HRAS, KRAS, and RET mutations were 259 (54%), 62 (13%), 13 (3%), 16 (3%), and 12 (2%), respectively. The BRAF V600E mutation (n = 257) was the predominant BRAF mutation. TERT promoter mutations, which are associated with tumor aggressiveness, were detected in 308 patients (64%). CONCLUSIONS: PTC was the most common histologic type of TC for which genetic profiling was performed in Japan, followed by ATC. Since the most common targetable mutation is the BRAF mutation, practical application of BRAF-targeted therapy can be an important treatment option for Japanese patients with TC.

BRCA2 reversion mutation confers resistance to olaparib in breast cancer.

Key Clinical Message: A rare missense mutation was identified as a reversion mutation using cancer genomic profiling and a suspected mechanism underlying resistance to olaparib in breast cancer. Abstract: A 34-year-old woman with breast cancer and BRCA2: p.Gln3047Ter was treated with olaparib. After tumor progression, cancer genomic profiling testing using liquid biopsy revealed BRCA2 p.Gln3047Ter and p.Gln3047Tyr, with 48.9% and 0.37% allele frequency, respectively. These findings shed light on reversion mutation as a mechanism of resistance to olaparib in breast cancer.

EGFR inhibition reverses resistance to lenvatinib in hepatocellular carcinoma cells.

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related death worldwide. Lenvatinib is approved as a first-line treatment for unresectable HCC. The therapeutic duration of lenvatinib is limited by resistance, but the underlying mechanism is unclear. To establish lenvatinib-resistant cells, Hep3B cells were initially treated with 3 µM lenvatinib. The concentration was gradually increased by 1 µM or 0.5 µM per week and it reached to 7.5 µM 2 months after the initial exposure to lenvatinib. The biological characteristics of these cells were analyzed by ERK activation in the MAPK signaling pathway and a human phospho-receptor tyrosine kinase (RTK) antibody array. Factors possibly related to lenvatinib resistance were analyzed using inhibitors, and cell proliferation was analyzed. We established lenvatinib-resistant HCC cells (LR cells) by long-term exposure to lenvatinib. Lenvatinib reduced ERK activation in the parent cells, but not in the LR cells. RTK array analysis showed that the activities of EGFR and insulin-like growth factor 1 receptor (IGF1R)/insulin receptor (INSR) were significantly increased in LR cells, whereas the activities of other RTKs were unchanged. Erlotinib, a widely used EGFR inhibitor, downregulated ERK activation in LR cells. The proliferation of LR cells will also be affected when lenvatinib is combined with erlotinib to treat LR cells. In contrast, inhibition of IGFR/INSR did not affect ERK activation or cell proliferation. Scavenging of reactive oxygen species (ROS) ameliorated the enhanced EGFR activation in LR cells. Lenvatinib resistance was induced by enhanced EGFR activation, possibly via ROS accumulation, in lenvatinib- resistant cells. These findings may enable the development of lenvatinib combination therapies for HCC.

Novel clip device for prevention of bleeding after endoscopic papillectomy.

Objectives: Recently, a novel clip device, SureClip® (Micro-Tech Co. Ltd., Nanjing, China), has been developed, which improved rotation and reopening performance. We aimed to assess the efficacy of the SureClip® in prophylactic closure of the mucosal break after endoscopic papillectomy (EP) for ampullary neoplasm. Methods: We retrospectively reviewed the medical records of 40 patients who underwent EP for ampullary neoplasms between October 2009 and March 2020. Prophylactic closure after resection was performed using the conventional clip between 2014 and 2018, and with the SureClip® after 2019. The baseline characteristics, techniques, outcomes, and complications of EP were analyzed. Results: The median age of the patients (25 males and 15 females) was 70 years. The en block resection rate was 82.5% and the curative resection rate was 80.0%. Histologically, 11 (27.5%) patients had malignancy. Prophylactic closure was performed in 29 (72.5%) patients (17 conventional clips, 12 SureClip®). Complications occurred in 18 (45.0%) patients, including postprocedure bleeding in 9 (22.5%) patients. However, no postprocedure bleeding was observed in the patients who received prophylactic closure using the SureClip® (p = 0.038). All other factors were not significantly correlated with postprocedure bleeding. The duration of hospital stay after EP was significantly shorter in patients treated with the SureClip® compared to those treated with a conventional clip or without clips (p < 0.05). Conclusions: In the present study, prophylactic clipping of the mucosal break using the SureClip® was effective in preventing bleeding after EP.

The Origin of Epithelium with Low-Grade Atypia in Early Gastric Cancer.

INTRODUCTION: Helicobacter pylori (HP) infection causes chronic inflammation and atrophy of the gastric mucosa and thus a high risk of gastric cancer (GC). With the increasing success of HP infection treatment, a larger number of GCs that develop after eradication can be assessed. Several studies have shown that epithelium with low-grade atypia (ELA) is a frequent characteristic of these GCs, but the origin of this condition is unknown. In this study, we compared the mucin phenotype, cellular proliferation, and p53 staining in ELA and cancerous tissues obtained from patients with GC with and without HP eradication. METHODS: The study population consisted of 23 patients with GC that developed after successful HP eradication therapy (eradicated group) and 24 patients with GC and HP infection (infected group). The prevalence of ELA was determined by hematoxylin and eosin staining. Tumor tissue and ELA samples were further analyzed by immunohistochemical staining for Muc5AC, Muc2, p53, and Ki-67. RESULTS: The ELA coverage rate was significantly higher in the eradicated group than in the infected group. Gastric-type mucin was frequently expressed by the ELA, and the mucin phenotypes of ELA and cancerous areas differed in 75% of cases. The Ki-67 labeling index was consistently lower in ELA than in the cancerous mucosa. Fourteen of 21 (66.7%) cancerous lesions, but only 3 ELA samples, were p53-positive. CONCLUSION: In most cases, ELA on the surfaces of GCs seems to have originated from normal gastric cells, not from cancer cells.

Potential roles of gastroesophageal reflux in patients with superficial esophageal squamous cell carcinoma without major causative risk factors.

BACKGROUND: Cigarette smoking, alcohol consumption, and Lugol-voiding lesions (LVLs) are the major causative risk factors of esophageal squamous cell carcinoma (ESCC); however, reports on ESCC cases unrelated to these risk factors are very limited. Here, we investigated the clinicopathological features and etiology of such cases. METHODS: We retrospectively analyzed 704 consecutive superficial ESCC tumors of 512 patients who were treated with endoscopic submucosal dissection. The enrolled patients were divided into two groups-the very low-risk (VLR)-group and risk (R)-group-based on the presence of the abovementioned risks. Clinical, endoscopic, and pathological characteristics and genetic findings were assessed in both groups. RESULTS: The VLR-group consisted of 21 (4.1%) patients, who were characteristically female. Patients in the VLR-group presented gastroesophageal reflux disease (GERD), hiatal hernia, and non-open-type atrophic gastritis, and were negative for Helicobacter pylori. We found unique endoscopic features-frequently observed in the posterior wall of the middle thoracic esophagus-with a linear shape that closely resembled the erosion-like form of GERD. Additionally, histopathological examination showed that these tumors presented atypical nuclei limited to the basal and parabasal layer, sequential to the surrounding changes that presented pathological chronic inflammation of esophagitis. Evaluation of somatic mutations in cancer-related genes using next-generation sequencing revealed that the positive carcinogenic potential (TP53 mutation) of the tumors was relatively frequent in the VLR-group. CONCLUSIONS: Our study suggests that ESCC without major causative factors is related to GERD, with no remarkable oncogenic difference.

Multiple-line Chemotherapy for a Patient with Unresectable Mucinous Cystic Neoplasm of the Pancreas.

A 74-year-old woman with a cyst in her pancreatic tail was referred to our hospital. Computed tomography confirmed a large cystic lesion with irregular wall thickening, abdominal lymph node swelling, and ascites. We diagnosed her with an unresectable mucinous cystic neoplasm, since ascites cytology revealed adenocarcinoma. The patient received chemotherapy up to the fifth line for 55.2 months. Gemcitabine plus nab-paclitaxel and modified FOLFIRINOX achieved a partial response with a progression-free survival time of 12.1 and 20.4 months, respectively. The overall survival time from the beginning of first-line chemotherapy was 69.4 months.

NAFLD exacerbates cholangitis and promotes cholangiocellular carcinoma in mice.

Nonalcoholic fatty liver disease (NAFLD) is an increasingly common condition, affecting up to 25% of the population worldwide. NAFLD has been linked to several conditions, including hepatic inflammation, fibrosis, and hepatocellular carcinoma (HCC), however the role of NAFLD in cholangitis and the development of cholangiocellular carcinoma (CCC) remains poorly understood. This study investigated whether a high-fat diet (HFD) promotes cholangitis and the development of CCC in mice. We used liver-specific E-cadherin gene (CDH1) knockout mice, CDH1∆Liv , which develop spontaneous inflammation in the portal areas along with periductal onion skin-like fibrosis, similar to that of primary sclerosing cholangitis (PSC). An HFD or normal diet (ND) was fed to CDH1∆Liv mice for 7 mo. In addition, CDH1∆Liv mice were crossed with LSL-KrasG12D mice, fed an HFD, and assessed in terms of liver tumor development. The extent of cholangitis and number of bile ductules significantly increased in mice fed an HFD compared with ND-administered CDH1∆Liv mice. The numbers of Sox9 and CD44-positive stem cell-like cells were significantly increased in HFD mice. LSL-KrasG12D /CDH1∆Liv HFD mice exhibited increased aggressiveness along with the development of numerous HCC and CCC, whereas LSL-KrasG12D /CDH1∆Liv ND mice showed several macroscopic tumors with both HCC and CCC components. In conclusion, NAFLD exacerbates cholangitis and promotes the development of both HCC and CCC in mice.

Loss of Pancreatic E-Cadherin Causes Pancreatitis-Like Changes and Contributes to Carcinogenesis.

BACKGROUND & AIMS: E-cadherin (Cdh1) is a key molecule for adherence required for maintenance of structural homeostasis. Loss of E-cadherin leads to poor prognosis and the development of resistance to chemotherapy in pancreatic cancer. Here, we evaluated the physiological and pathologic roles of E-cadherin in the pancreas. METHODS: We crossbred Ptf1a-Cre mice with Cdh1f/f mice to examine the physiological roles of E-cadherin in the pancreas. In addition, we crossbred these mice with LSL-KrasG12D/+ mice (PKC) to investigate the pathologic roles of E-cadherin. We also generated a tamoxifen-inducible system (Ptf1a-CreERT model). Organoids derived from these models using lentiviral transduction were analyzed for immunohistochemical features. Established cell lines from these organoids were analyzed for migratory and invasive activities as well as gene expression by complementary DNA microarray analyses. RESULTS: None of the Ptf1a-Cre mice crossbred with Cdh1f/f mice survived for more than 28 days. We observed aberrant epithelial tubules that resembled the structure of acinar-to-ductal metaplasia after postnatal day 6, showing features of pancreatitis. All of the PKC mice died within 10 days. We observed tumorigenicity with increasing stroma-like aggressive tumors. Ptf1a-CreERT models showed that deletion of E-cadherin led to earlier pancreatic intraepithelial neoplasm formation. Cells established from PKC organoids had greater migratory and invasive activities, and these allograft tumors showed a poorly differentiated phenotype. Gene expression analysis indicated that Hdac1 was up-regulated in PKC cell lines and a histone deacetylase 1 inhibitor suppressed PKC cell proliferation. CONCLUSIONS: Under physiological conditions, E-cadherin is important for maintaining the tissue homeostasis of the pancreas. Under pathologic conditions with mutational Kras activation, E-cadherin plays an important role in tumor formation via the acquisition of tumorigenic activity.

Quantitative monitoring of circulating tumor DNA in patients with advanced pancreatic cancer undergoing chemotherapy.

According to cancer genome sequences, more than 90% of cases of pancreatic ductal adenocarcinoma (PDAC) harbor active KRAS mutations. Digital PCR (dPCR) enables accurate detection and quantification of rare mutations. We assessed the dynamics of circulating tumor DNA (ct-DNA) in patients with advanced PDAC undergoing chemotherapy using dPCR. KRAS G12/13 mutation was assayed by dPCR in 47 paired tissue- and ct-DNA samples. The 21 patients were subjected to quantitative ct-DNA monitoring at 4 to 8-week intervals during chemotherapy. KRAS mutation was detected in 45 of those 47 patients using tissue DNA. In the KRAS mutation-negative cases, next-generation sequencing revealed KRAS Q61K and NRAS Q61R mutations. KRAS mutation was detected in 23/45 cases using ct-DNA (liver or lung metastasis, 18/19; mutation allele frequency [MAF], 0.1%-31.7%; peritoneal metastasis, 3/9 [0.1%], locally advanced, 2/17 [0.1%-0.2%]). In the ct-DNA monitoring, the MAF value changed in concordance with the disease state. In the 6 locally advanced cases, KRAS mutation appeared concurrently with liver metastasis. Among the 6 cases with liver metastasis, KRAS mutation disappeared during the duration of stable disease or a partial response, and reappeared at the time of progressive disease. The median progression-free survival was longer in cases in which KRAS mutation disappeared after an initial course of chemotherapy than in those in which it was continuously detected (248.5 vs 50 days, P < .001). Therefore, ct-DNA monitoring enables continuous assessment of disease state and could have prognostic utility during chemotherapy.

Predictive value of ERCC1, ERCC2, ERCC4, and glutathione S-Transferase Pi expression for the efficacy and safety of FOLFIRINOX in patients with unresectable pancreatic cancer.

The platinum-based chemotherapy regimen FOLFIRINOX (leucovorin, fluorouracil, irinotecan, and oxaliplatin) is currently used as a standard treatment for patients with unresectable pancreatic cancer. FOLFIRINOX is associated with severe toxicities, including neutropenia, febrile neutropenia, and anorexia; however, there are currently no reliable biomarkers to predict its efficacy and safety. Several studies of patients with various cancers have shown that tumor expression of excision repair cross-complementing (ERCC) proteins and glutathione S-transferase Pi (GSTPi) correlates with the response to platinum-based chemotherapies. Therefore, in this study, we examined the associations between expression of ERCC proteins and GSTPi and the safety and efficacy of FOLFIRINOX in 34 patients with unresectable pancreatic cancer. ERCC1, ERCC2, ERCC4, and GSTPi expression were examined by immunohistochemical staining of tumor specimens and the results were correlated with overall survival, progression-free survival, response rate, disease control rate, and the frequency of grade 3-4 neutropenia and non-hematologic toxicities. We found that ERCC1, ERCC2, ERCC4, and GSTPi were expressed in tumor samples from 64%, 24%, 18%, and 64% of patients, respectively. Notably, there were no statistically significant associations between the expression pattern of any of the proteins and either the clinical outcomes or the frequency of grade 3-4 neutropenia or grade 3-4 anorexia. Collectively, these data indicate that tumor expression of ERCC1, ERCC2, ERCC4, and GSTPi does not predict the safety or efficacy of FOLFIRINOX in patients with pancreatic cancer.

Activation of Signal Transduction and Activator of Transcription 3 Signaling Contributes to Helicobacter-Associated Gastric Epithelial Proliferation and Inflammation.

BACKGROUND/AIM: Although IL-6-mediated activation of the signal transduction and activator of transcription 3 (STAT3) axis is involved in inflammation and cancer, the role of STAT3 in Helicobacter-associated gastric inflammation and carcinogenesis is unclear. This study investigated the role of STAT3 in gastric inflammation and carcinogenesis and examined the molecular mechanism of Helicobacter-induced gastric phenotypes. METHODS: To evaluate the contribution of STAT3 to gastric inflammation and carcinogenesis, we used wild-type (WT) and gastric epithelial conditional Stat3-knockout (Stat3Δgec ) mice. Mice were infected with Helicobacter felis and euthanized at 18 months postinfection. Mouse gastric organoids were treated with recombinant IL-6 (rIL-6) or rIL-11 and a JAK inhibitor (JAKi) to assess the role of IL-6/STAT3 signaling in vitro. RESULTS: Inflammation and mucous metaplasia were more severe in WT mice than in Stat3Δgec mice. The epithelial cell proliferation rate and STAT3 activation were increased in WT mice. Application of rIL-6 and rIL-11 induced expression of intestinal metaplasia-associated genes, such as Tff2; this induction was suppressed by JAKi administration. CONCLUSIONS: Loss of STAT3 signaling in the gastric mucosa leads to decreased epithelial cell proliferation, atrophy, and metaplasia in the setting of Helicobacter infection. Therefore, activation of STAT3 signaling may play a key role in Helicobacter-associated gastric carcinogenesis.

Overexpression of HER2 in the pancreas promotes development of intraductal papillary mucinous neoplasms in mice.

Pancreatic ductal adenocarcinoma (PDA) has a 5-year survival rate of less than 5% and is the sixth leading cause of cancer death. Although KRAS mutations are one of the major driver mutations in PDA, KRAS mutation alone is not sufficient to induce invasive pancreatic cancer in mice model. HER2, also known as ERBB2, is a receptor tyrosine kinase, and overexpression of HER2 is associated with poor clinical outcomes in pancreatic cancer. However, no report has shown whether HER2 and its downstream signaling contributes to the pancreatic cancer development. By immunohistochemical analysis in human cases, HER2 protein expression was detected in 40% of PDAs and 29% of intraductal papillary mucinous carcinomas, another type of pancreatic cancer. In a mouse model, we showed overexpression of activated HER2 (HER2 NT ) in the pancreas, in which cystic neoplastic lesions resembling intraductal papillary mucinous neoplasm-like lesions in humans had developed. We also found that HER2 NT cooperated with oncogenic Kras to accelerate the development of pancreatic intraepithelial neoplasms. In addition, using pancreatic organoids in 3D cultures, we found that organoids cultured from HER2 NT /Kras double transgenic mice showed proliferative potential and tumorigenic ability cooperatively. HER2-signaling inhibition was suggested to be an new therapeutic target in some types of PDAs.

Influence of NUDT15 variants on hematological pictures of patients with inflammatory bowel disease treated with thiopurines.

AIM: The single nucleotide polymorphism (SNP) c.415C>T in exon 3 of NUDT15 affects thiopurine-induced leukopenia in Asian patients with Crohn's disease. Meanwhile, three additional genetic variants of NUDT15 were reported in patients with acute lymphoblastic leukemia. We evaluated the effects of these additional genetic variants of NUDT15 in patients with inflammatory bowel disease (IBD) treated with thiopurines. METHODS: Ninety-six Japanese patients with IBD were enrolled. Genotyping for the NUDT15 and TPMT genes was performed using Custom TaqMan SNP genotyping assays or Sanger sequencing. The changes in white blood cell (WBC) count, mean corpuscular volume (MCV), platelet count, hemoglobin, CRP, amylase, albumin, AST, ALT, and ESR were evaluated. RESULTS: Genetic variants of exon 1 and exon 3 of NUDT15 were identified in 24 of 96 patients (25.0%). C.52G > A and c.36_37insGGAGTC in exon 1 were found in three patients each. All three patients with c.36_37insGGAGTC in exon 1 were heterozygotes of p.Arg139Cys in exon 3. Eighteen patients had p.Arg139Cys in exon 3 alone. The WBC count gradually decreased after initiation of thiopurine treatment in the mutated cases (n = 24), and was significantly lower at 6, 8, 10, and 16 wk (P = 0.0271, 0.0037, 0.0051, and 0.0185, respectively). The WBC counts were also evaluated in patients with and without prednisolone treatment. In the patients with prednisolone treatment, the WBC count tended to show a greater decrease in the mutated cases, with significant differences at 8 and 10 wk (P = 0.012 and 0.029, respectively). In the patients without prednisolone treatment, the WBC count was significantly lower at 2, 4, 8, and 14 wk in mutated cases (P = 0.0196, 0.0182, 0.0237 and 0.0241, respectively). MCV increased after starting thiopurine treatment in the mutated cases, and was significantly higher at 10 wk (P = 0.0085). Platelet count, hemoglobin, CRP, amylase, albumin, AST, ALT and ESR did not differ significantly between the wild-type and mutated cases. TPMT mutations were not found in any of the patients. CONCLUSION: Mutations in exon 1 of NUDT15 also affect thiopurine-induced leukopenia in patients with IBD. To discuss thiopurine-induced leukopenia in more detail, investigation of SNPs in both exon 1 and exon 3 of NUDT15 is needed.

Correction to: Helicobacter-induced gastric inflammation alters the properties of gastric tissue stem/progenitor cells.

CORRECTION: Unfortunately, the original article [1] contained an error incorporated during production. A duplicated version of Table 1 was published in place of Table 2. Table 2 has been corrected in the original article and is also included correctly below.

Helicobacter-induced gastric inflammation alters the properties of gastric tissue stem/progenitor cells.

BACKGROUND: Although Helicobacter-induced gastric inflammation is the major predisposing factor for gastric carcinogenesis, the precise mechanism by which chronic gastritis causes gastric cancer remains unclear. Intestinal and spasmolytic polypeptide-expressing metaplasia (SPEM) is considered as precancerous lesions, changes in epithelial tissue stem/progenitor cells after chronic inflammation has not been clarified yet. In this study, we utilized three-dimensional gastric epithelial cell culture systems that could form organoids, mimicking gastric epithelial layer, and characterized the changes in epithelial cells after chronic Helicobacter felis infection. METHODS: We used three mice model; 1) long-term H. felis infection, 2) H. felis eradication, and 3) MNU chemical carcinogenesis model. We performed cRNA microarray analysis after organoid culture, and analyzed the effects of chronic gastric inflammation on tissue stem cells, by the size of organoid, mRNA expression profile and immunohistochemical analysis. RESULTS: The number of organoids cultured from gastric epithelial cells was significantly higher in organoids isolated from H. felis-infected mice compared with those from uninfected gastric mucosa. Based on the mRNA expression profile, we found that possible stem cell markers such as Cd44, Dclk1, and genes associated with the intestinal phenotype, such as Villin, were increased in organoids isolated from H. felis-infected mucosa compared with the control. The upregulation of these genes were cancelled after H. felis eradication. In a xenograft model, tumors were generated only from organoids cultured from carcinogen-treated gastric mucosa, not from H. felis infected mucosa or control organoids. CONCLUSIONS: Our results suggested that, as a possible mechanism of gastric carcinogenesis, chronic inflammation induced by H. felis infection increased the number of tissue stem/progenitor cells and the expression of stem cell markers. These findings suggest that chronic inflammation may alter the direction of differentiation toward undifferentiated state and that drawbacks may enable cells to redifferentiate to intestinal metaplasia or neoplasia.

Familial Adenomatous Polyposis with Multiple Helicobacter-negative Early Gastric Cancers Treated by Endoscopic Submucosal Dissection.

Stomach cancer rarely develops in patients with familial adenomatous polyposis (FAP), and Helicobacter pylori infection may increase the risk of FAP-related gastric cancer. We describe the case of a 64-year-old woman who developed multiple synchronous early gastric cancers without H. pylori infection. Nine cancer lesions were successfully treated by endoscopic submucosal dissection. An immunohistochemical analysis revealed that the tumors were positive for mucin (MUC)2, MUC6, and CDX2, but negative for MUC5AC, suggesting that the tumors were gastrointestinal mixed type. Periodical endoscopic surveillance is important for the detection of cancers at an early stage.