Orchestration of myeloid-derived suppressor cells in the tumor microenvironment by ubiquitous cellular protein TCTP released by tumor cells.

One of most challenging issues in tumor immunology is a better understanding of the dynamics in the accumulation of myeloid-derived suppressor cells (MDSCs) in the tumor microenvironment (TIME), as this would lead to the development of new cancer therapeutics. Here, we show that translationally controlled tumor protein (TCTP) released by dying tumor cells is an immunomodulator crucial to full-blown MDSC accumulation in the TIME. We provide evidence that extracellular TCTP mediates recruitment of the polymorphonuclear MDSC (PMN-MDSC) population in the TIME via activation of Toll-like receptor-2. As further proof of principle, we show that inhibition of TCTP suppresses PMN-MDSC accumulation and tumor growth. In human cancers, we find an elevation of TCTP and an inverse correlation of TCTP gene dosage with antitumor immune signatures and clinical prognosis. This study reveals the hitherto poorly understood mechanism of the MDSC dynamics in the TIME, offering a new rationale for cancer immunotherapy.

Identification of liver cancer progenitors whose malignant progression depends on autocrine IL-6 signaling.

Hepatocellular carcinoma (HCC) is a slowly developing malignancy postulated to evolve from premalignant lesions in chronically damaged livers. However, it was never established that premalignant lesions actually contain tumor progenitors that give rise to cancer. Here, we describe isolation and characterization of HCC progenitor cells (HcPCs) from different mouse HCC models. Unlike fully malignant HCC, HcPCs give rise to cancer only when introduced into a liver undergoing chronic damage and compensatory proliferation. Although HcPCs exhibit a similar transcriptomic profile to bipotential hepatobiliary progenitors, the latter do not give rise to tumors. Cells resembling HcPCs reside within dysplastic lesions that appear several months before HCC nodules. Unlike early hepatocarcinogenesis, which depends on paracrine IL-6 production by inflammatory cells, due to upregulation of LIN28 expression, HcPCs had acquired autocrine IL-6 signaling that stimulates their in vivo growth and malignant progression. This may be a general mechanism that drives other IL-6-producing malignancies.

Satellite double-stranded RNA induces mesenchymal transition in pancreatic cancer by regulating alternative splicing.

Human satellite II (HSATII), composed of tandem repeats in pericentromeric regions, is aberrantly transcribed in epithelial cancers, particularly pancreatic cancer. Dysregulation of repetitive elements in cancer tissues can facilitate incidental dsRNA formation; however, it remains controversial whether dsRNAs play tumor-promoting or tumor-suppressing roles during cancer progression. Therefore, we focused on the double-stranded formation of HSATII RNA and explored its molecular function. The overexpression of double-stranded HSATII (dsHSATII) RNA promoted mesenchymal-like morphological changes and enhanced the invasiveness of pancreatic cancer cells. We identified an RNA-binding protein, spermatid perinuclear RNA-binding protein (STRBP), which preferentially binds to dsHSATII RNA rather than single-stranded HSATII RNA. The mesenchymal transition of dsHSATII-expressing cells was rescued by STRBP overexpression. Mechanistically, STRBP is involved in the alternative splicing of genes associated with epithelial-mesenchymal transition (EMT). We also confirmed that isoform switching of CLSTN1, driven by dsHSATII overexpression or STRBP depletion, induced EMT-like morphological changes. These findings reveal a novel tumor-promoting function of dsHSATII RNA, inducing EMT-like changes and cell invasiveness, thus enhancing our understanding of the biological significance of aberrant expression of satellite arrays in malignant tumors.

Deep learning and digital pathology powers prediction of HCC development in steatotic liver disease.

BACKGROUND AND AIMS: Identifying patients with steatotic liver disease who are at a high risk of developing HCC remains challenging. We present a deep learning (DL) model to predict HCC development using hematoxylin and eosin-stained whole-slide images of biopsy-proven steatotic liver disease. APPROACH AND RESULTS: We included 639 patients who did not develop HCC for ≥7 years after biopsy (non-HCC class) and 46 patients who developed HCC <7 years after biopsy (HCC class). Paired cases of the HCC and non-HCC classes matched by biopsy date and institution were used for training, and the remaining nonpaired cases were used for validation. The DL model was trained using deep convolutional neural networks with 28,000 image tiles cropped from whole-slide images of the paired cases, with an accuracy of 81.0% and an AUC of 0.80 for predicting HCC development. Validation using the nonpaired cases also demonstrated a good accuracy of 82.3% and an AUC of 0.84. These results were comparable to the predictive ability of logistic regression model using fibrosis stage. Notably, the DL model also detected the cases of HCC development in patients with mild fibrosis. The saliency maps generated by the DL model highlighted various pathological features associated with HCC development, including nuclear atypia, hepatocytes with a high nuclear-cytoplasmic ratio, immune cell infiltration, fibrosis, and a lack of large fat droplets. CONCLUSIONS: The ability of the DL model to capture subtle pathological features beyond fibrosis suggests its potential for identifying early signs of hepatocarcinogenesis in patients with steatotic liver disease.

Integrated policy of medical expense subsidies and clinical registry for patients with liver cancer and decompensated cirrhosis in Japan.

Chronic hepatitis B and C are among the most significant infectious diseases worldwide, and are major risk factors for liver cirrhosis and liver cancer. In Japan, comprehensive hepatitis measures are implemented for the testing and treatment of viral hepatitis, thus enabling the early diagnosis of liver cancer. Nevertheless, patients with decompensated cirrhosis and liver cancer often have unfavorable prognoses and require repetitive long-term treatment. In fiscal year 2018, an integrated policy of medical expense subsidies and research was established in Japan that aimed to alleviate patients' financial burden and launch the clinical registry of advanced liver disease. Over time, updates to the eligibility for the subsidy increased access to patients and has led to an increased number of beneficiaries. Additionally, the accumulation of clinical data in the registry has revealed the treatment choices for these diseases. However, the disparities in efforts across prefectures have also become evident. Raising public awareness of the policy and tightening the multisector healthcare network are keys to success in supporting qualifying patients with advanced liver disease.

Differential peripheral memory T cell subsets sensitively indicate the severity of nonalcoholic fatty liver disease.

AIM: Differential patterns of peripheral memory T cell subsets in nonalcoholic fatty liver disease (NAFLD) were assessed using flow cytometry (FCM) to elucidate their association with NAFLD severity and provide a new noninvasive method to sensitively detect the disease severity in addition to existing biomarkers. METHODS: We assessed the differential frequencies of peripheral memory T cell subsets in 103 patients with NAFLD according to the degree of liver fibrosis (FIB) using FCM analysis. We focused on the following populations: CCR7+ CD45RA+ naïve T, CCR7+ CD45RA- central memory T cells (TCM), CCR7- CD45RA- effector memory T, and CCR7- CD45RA+ terminally differentiated effector memory T (TEMRA) cells in CD4+ and CD8+ T, Th1, Th2, and Th17 cells, respectively. To evaluate the pathological progression of the disease, these frequencies were also examined according to the degree of the NAFLD activity score (NAS). RESULTS: Several significant correlations were observed between laboratory parameters and peripheral memory T lymphocyte frequencies according to the degree of liver FIB and NAS in NAFLD. In univariate and multivariate analyses, the frequency of CD8+ TEMRA cells predicted severe FIB, and the predictive power was validated in an independent cohort. Furthermore, the frequencies of several memory T cell subsets sensitively indicated the pathological progression of NAFLD (Th17 TCM: steatosis, CD4+ TCM: lobular inflammation, and CD8+ TEMRA and effector memory T cells: hepatocellular ballooning). CONCLUSIONS: Our results suggest that the analysis of peripheral memory T lymphocyte frequencies can noninvasively predict severe FIB and sensitively indicate the pathological progression of NAFLD.

Hepatitis C virus modulates signal peptide peptidase to alter host protein processing.

Immunoevasins are viral proteins that prevent antigen presentation on major histocompatibility complex (MHC) class I, thus evading host immune recognition. Hepatitis C virus (HCV) evades immune surveillance to induce chronic infection; however, how HCV-infected hepatocytes affect immune cells and evade immune recognition remains unclear. Herein, we demonstrate that HCV core protein functions as an immunoevasin. Its expression interfered with the maturation of MHC class I molecules catalyzed by the signal peptide peptidase (SPP) and induced their degradation via HMG-CoA reductase degradation 1 homolog, thereby impairing antigen presentation to CD8+ T cells. The expression of MHC class I in the livers of HCV core transgenic mice and chronic hepatitis C patients was impaired but was restored in patients achieving sustained virological response. Finally, we show that the human cytomegalovirus US2 protein, possessing a transmembrane region structurally similar to the HCV core protein, targets SPP to impair MHC class I molecule expression. Thus, SPP represents a potential target for the impairment of MHC class I molecules by DNA and RNA viruses.

Machine learning for individualized prediction of hepatocellular carcinoma development after the eradication of hepatitis C virus with antivirals.

BACKGROUND AND AIMS: Accurate risk stratification for hepatocellular carcinoma (HCC) after achieving a sustained viral response (SVR) is necessary for optimal surveillance. We aimed to develop and validate a machine learning (ML) model to predict the risk of HCC after achieving an SVR in individual patients. METHODS: In this multicenter cohort study, 1742 patients with chronic hepatitis C who achieved an SVR were enrolled. Five ML models were developed including DeepSurv, gradient boosting survival analysis, random survival forest (RSF), survival support vector machine, and a conventional Cox proportional hazard model. Model performance was evaluated using Harrel' c-index and was externally validated in an independent cohort (977 patients). RESULTS: During the mean observation period of 5.4 years, 122 patients developed HCC (83 in the derivation cohort and 39 in the external validation cohort). The RSF model showed the best discrimination ability using seven parameters at the achievement of an SVR with a c-index of 0.839 in the external validation cohort and a high discriminative ability when the patients were categorized into three risk groups (P <0.001). Furthermore, this RSF model enabled the generation of an individualized predictive curve for HCC occurrence for each patient with an app available online. CONCLUSIONS: We developed and externally validated an RSF model with good predictive performance for the risk of HCC after an SVR. The application of this novel model is available on the website. This model could provide the data to consider an effective surveillance method. Further studies are needed to make recommendations for surveillance policies tailored to the medical situation in each country. IMPACT AND IMPLICATIONS: A novel prediction model for HCC occurrence in patients after hepatitis C virus eradication was developed using machine learning algorithms. This model, using seven commonly measured parameters, has been shown to have a good predictive ability for HCC development and could provide a personalized surveillance system.

MNX1-HNF1B Axis Is Indispensable for Intraductal Papillary Mucinous Neoplasm Lineages.

BACKGROUND & AIMS: Chromatin architecture governs cell lineages by regulating the specific gene expression; however, its role in the diversity of cancer development remains unknown. Among pancreatic cancers, pancreatic ductal adenocarcinoma (PDAC) and intraductal papillary mucinous neoplasms (IPMN) with an associated invasive carcinoma (IPMNinv) arise from 2 distinct precursors, and their fundamental differences remain obscure. Here, we aimed to assess the difference of chromatin architecture regulating the transcriptional signatures or biological features in pancreatic cancers. METHODS: We established 28 human organoids from distinct subtypes of pancreatic tumors, including IPMN, IPMNinv, and PDAC. We performed exome sequencing (seq), RNA-seq, assay for transposase-accessible chromatin-seq, chromatin immunoprecipitation-seq, high-throughput chromosome conformation capture, and phenotypic analyses with short hairpin RNA or clustered regularly interspaced short palindromic repeats interference. RESULTS: Established organoids successfully reproduced the histology of primary tumors. IPMN and IPMNinv organoids harbored GNAS, RNF43, or KLF4 mutations and showed the distinct expression profiles compared with PDAC. Chromatin accessibility profiles revealed the gain of stomach-specific open regions in IPMN and the pattern of diverse gastrointestinal tissues in IPMNinv. In contrast, PDAC presented an impressive loss of accessible regions compared with normal pancreatic ducts. Transcription factor footprint analysis and functional assays identified that MNX1 and HNF1B were biologically indispensable for IPMN lineages. The upregulation of MNX1 was specifically marked in the human IPMN lineage tissues. The MNX1-HNF1B axis governed a set of genes, including MYC, SOX9, and OLFM4, which are known to be essential for gastrointestinal stem cells. High-throughput chromosome conformation capture analysis suggested the HNF1B target genes to be 3-dimensionally connected in the genome of IPMNinv. CONCLUSIONS: Our organoid analyses identified the MNX1-HNF1B axis to be biologically significant in IPMN lineages.

Impact of a Novel Digital Therapeutics System on Nonalcoholic Steatohepatitis: The NASH App Clinical Trial.

INTRODUCTION: Management of nonalcoholic steatohepatitis (NASH) is a currently unmet clinical need. Digital therapeutics (DTx) is an emerging class of medicine that delivers evidence-based therapeutic interventions. This study was aimed at investigating the efficacy of DTx in patients with NASH. METHODS: We conducted a multicenter, single-arm, 48-week trial in 19 patients with biopsy-confirmed NASH. All patients received a DTx intervention with a newly developed smartphone application. The primary endpoint was change in the nonalcoholic fatty liver disease activity score (NAS) without worsening of liver fibrosis. The secondary endpoints included improvement of the NAS by ≥2 points without worsening of liver fibrosis, change in the body weight, and regression of fibrosis. RESULTS: After the 48-week DTx intervention, improvement of the NAS was observed in 68.4% (13/19) of patients. The mean change in the NAS from baseline to the end of the intervention was -2.05 ± 1.96 ( P < 0.001 when compared with the threshold of -0.7). A decrease in the NAS by ≥ 2 points was achieved in 11 (57.9%). The average weight loss at the end of the intervention was 8.3% ( P < 0.001). Reduction of the fibrosis stage was observed in 58.3% when the analysis was limited to patients with stage F2/3 fibrosis. There were no serious adverse events that could be considered as being related to the DTx intervention. DISCUSSION: DTx for NASH was found to be highly efficacious and well-tolerated. Further evaluation of the DTx intervention for NASH in a phase 3 trial is warranted.

A prospective multicenter phase II study of FOLFIRINOX as a first-line treatment for patients with advanced and recurrent biliary tract cancer.

Given the promising activity and tolerability of FOLFIRINOX as a second-line treatment for advanced biliary tract cancer (BTC), it can be an attractive first-line treatment option as well. This is a single-arm, open-label, multicenter phase II study to evaluate the safety and efficacy of FOLFIRINOX as a first-line treatment for patients with advanced BTC. Primary endpoint was progression-free survival (PFS), and the secondary endpoints included overall survival (OS), tumor response and safety. This study defined primary endpoint might be met when the lower limit value of 80% confidence interval [CI] of the median PFS ≥ 6.0 months. Between June 2016 and March 2020, 35 BTC patients (21 intrahepatic, 10 extrahepatic, 2 gallbladder, 2 ampulla) including 26 unresectable and 9 recurrent disease were enrolled. After a median follow-up of 13.9 months, the median PFS and OS were 7.4 (80% CI, 5.5-7.5) and 14.7 (80% CI, 11.8-15.7) months, respectively. Complete response was achieved in 1 (2.9%) and partial response in 10 (28.6%), giving an objective response rate of 31.4% and disease control rate of 74.3%. Major grade 3-4 adverse events included neutropenia (54.3%), leukopenia (34.4%), febrile neutropenia (17.1%), thrombocytopenia (8.6%), cholangitis (8.6%), anemia, nausea, diarrhea, and peripheral sensory neuropathy (2.9% each). FOLFIRINOX was well tolerable in patients with advanced BTC, however, this study did not meet the primary endpoint to conduct a phase III trial. Thus, further explorations are required to find a subset of patients and/or certain clinical scenario which might be beneficial from FOLFIRINOX.

Treatment and outcome of hepatorenal syndrome in Japan: a retrospective cohort study using a national inpatient database.

BACKGROUND: Hepatorenal syndrome (HRS) is a life-threatening complication of end-stage liver disease. This study aimed to clarify the status of HRS in Japan by analyzing the Japanese Diagnosis Procedure Combination database. METHODS: Patients hospitalized for cirrhosis and HRS from July 2010 to March 2019 were sampled. They were divided into two groups according to their prognosis upon discharge: the transplant-free survival group and the death or liver transplantation group. The two groups' baseline patient characteristics and treatments were compared. RESULTS: The mean age of the 1,412 participants was 67.3 years (standard deviation: 12.3 years), and 65.4% were male. The Child-Pugh grades was B and C in 18.8% and 81.2%, respectively. Hepatocellular carcinoma was present in 27.1% of the patients, and the proportion of spontaneous bacterial peritonitis was 2.3%. Albumin, noradrenaline, and dopamine were administered to 57.9%, 8.0%, and 14.9% of the patients, respectively; 7.0% of the patients underwent renal replacement therapy; and 5.0% were admitted to the intensive care unit. Intravenous antibiotics were administered to 30.8% of the patients. A total of 925 patients (65.5%) died or underwent liver transplantation. In addition to a higher proportion of patients with poor baseline liver function, the death or liver transplantation group included more males, patients with hepatocellular carcinoma, and those with spontaneous bacterial peritonitis. CONCLUSIONS: HRS in Japan has a high mortality rate. Albumin was administered to over 50% of participants. Although noradrenaline is recommended in Japanese clinical guidelines, dopamine was more frequently used as a vasoconstrictor in clinical practice.

Transcriptome analysis reveals the essential role of NK2 homeobox 1/thyroid transcription factor 1 (NKX2-1/TTF-1) in gastric adenocarcinoma of fundic-gland type.

BACKGROUND: Gastric adenocarcinoma of fundic-gland type (GA-FG) is a gastric malignancy with little relation to Helicobacter pylori. Clinical characteristics of GA-FG have been established, but molecular mechanisms leading to tumorigenesis have not yet been elucidated. METHODS: We subjected three GA-FG tumors-normal mucosa pairs to microarray analysis. Network analysis was performed for the top 30 up-regulated gene transcripts, followed by immunohistochemical staining to confirm the gene expression analysis results. AGS and NUGC4 cells were transfected with the gene-encoding NK2 homeobox 1/thyroid transcription factor 1 (NKX2-1/TTF-1) to evaluate transcriptional changes in its target genes. RESULTS: Comprehensive gene expression analysis identified 1410 up-regulated and 1395 down-regulated gene probes with ≥ two-fold difference in expression. Among the top 30 up-regulated genes in GA-FG, we identified transcription factor NKX2-1/TTF-1, a master regulator of lung/thyroid differentiation, together with surfactant protein B (SFTPB), SFTPC, and secretoglobin family 3A member 2(SCGB3A2), which are regulated by NKX2-1/TTF-1. Immunohistochemical analysis of 16 GA-FG specimens demonstrated significantly higher NKX2-1/TTF-1 and SFTPB levels, as compared to that in adjacent normal mucosa (P < 0.05), while SCGB3A2 levels did not differ (P = 0.341). Transduction of NKX2-1/TTF-1 into AGS and NUGC4 cells induced transactivation of SFTPB and SFTPC, indicating that NKX2-1/TTF-1 can function as normally in gastric cells as it can in the lung cells. CONCLUSIONS: Our first transcriptome analysis of GA-FG indicates significant expression of NKX2-1/TTF1 in GA-FG. Immunohistochemistry and cell biology show ectopic expression and normal transactivation ability of NKX2-1/TTF-1, suggesting that it plays an essential role in GA-FG development.

Triglyceride level and soft drink consumption predict nonalcoholic fatty liver disease in nonobese male adolescents.

AIM: Differential metabolic risk factors of nonalcoholic fatty liver disease (NAFLD) in nonobese male adolescents were analyzed examining relationships between NAFLD and clinical parameters of metabolic syndrome, including exercise and soft drink consumption, in male adolescents. METHODS: In total, 134 male university students (nonobese, n = 78; obese, n = 56) who underwent the first-year health checkup were divided into the NAFLD and non-NAFLD groups based on abdominal ultrasonography (AUS) findings. Relationships between NAFLD and metabolic parameters, including body mass index (BMI) and AUS score, were examined in nonobese students. RESULTS: Metabolic factors associated with hypertension, abdominal fat, liver damage, dyslipidemia, and impaired glucose tolerance were significantly less common in nonobese students than in obese students. The aforementioned factors and soft drink consumption were significantly more common in the NAFLD group than in the non-NAFLD group. The univariate and multivariate analyses of nonobese students showed that the triglyceride level (odds ratio [OR], 1.06; 95% confidence interval [CI], 1.01-1.10, p = 0.001) was higher and soft drink consumption (OR, 36.8; 95% CI, 3.69-368, p < 0.001) was more common in the NAFLD group than the non-NAFLD group. CONCLUSIONS: Triglyceride level and soft drink consumption could aid in the detection of NAFLD in nonobese male adolescents. Our findings could provide useful information related to NAFLD and metabolic syndrome in nonobese adolescents.

Steroid administration for ischemic complications after radiofrequency ablation: A retrospective study.

AIM: The aim of this study was to evaluate the effects of steroids on ischemic complications after radiofrequency ablation. METHODS: A total of 58 patients with ischemic complications were divided into two groups according to corticosteroid use or non-use. RESULTS: A total of 13 patients who were administered steroids had a shorter duration of fever than those who were not administered steroids (median 6.0 vs. 2.0 days; p < 0.001). Linear regression analysis showed that steroid administration was associated with a reduction of 3.9 days in the duration of fever (p = 0.008). CONCLUSIONS: Steroid administration for ischemic complications after radiofrequency ablation may reduce the risk of fatal outcomes by blocking systemic inflammatory reactions.

Reduced DEFA5 Expression and STAT3 Activation Underlie the Submucosal Invasion of Early Gastric Cancers.

INTRODUCTION: Submucosal invasion is a core hallmark of early gastric cancer (EGC) with poor prognosis. However, the molecular mechanism of the progression from intramucosal gastric cancer (IMGC) to early submucosal-invasive gastric cancer (SMGC) is not fully understood. The objective of this study was to identify genes and pathways involved in the submucosal invasion in EGC using comprehensive gene expression analysis. METHODS: Gene expression profiling was performed for eight cases of IMGC and eight cases of early SMGC with submucosal invasion ≥500 µm. To validate the findings of gene expression analysis and to examine the gene expression pattern in tissues, immunohistochemical (IHC) staining was performed for 50 cases of IMGC and SMGC each. RESULTS: Gene expression analysis demonstrated that the expression levels of small intestine-specific genes were significantly decreased in SMGC. Among them, defensin alpha 5 (DEFA5) was the most downregulated gene in SMGC, which was further validated in SMGC tissues by IHC staining. Gene set enrichment analysis showed a strong association between SMGC, the JAK-STAT signaling pathway, and the upregulation of STAT3-activating cytokines. The expression of phosphorylated STAT3 was significant in the nucleus of tumor cells in SMGC tissues but not in areas expressing DEFA5. CONCLUSION: The results of this study strongly suggest that the downregulation of DEFA5 and the activation of STAT3 play a significant role in the submucosal invasion of EGC.

Poor tolerability of lenvatinib in elderly patients ≥80 years old with hepatocellular carcinoma: A multicenter observational study.

INTRODUCTION: Management of elderly patients with cancer has become a global issue. We investigated the safety and tolerability of lenvatinib in hepatocellular carcinoma (HCC) patients ≥80 years old. METHODS: We retrospectively evaluated 61 HCC patients and divided them into 2 groups: an elderly group (n = 13, ≥80 years old) and a younger group (n = 48, <80 years old). We compared the adverse events (AEs), administration period, dose intensity, objective response, and progression-free survival (PFS) between the two groups. RESULTS: The discontinuation of lenvatinib due to AEs was more frequent in the elderly group (8/13, 61.5%) than in the younger group (10/48, 20.8%) (P = 0.0043). Fatigue and appetite loss accounted for half of the cases discontinued due to AEs in the elderly group. The elderly group had a significantly lower 8-week-delivered dose intensity/body surface area ratio (147.2) and 8-week-relative dose intensity (50.0%) than those in the younger group (267.4, 67%) (P = 0.003, 0.029). The objective response rate was significantly lower in the elderly group (15.4%) than in the younger group (61.5%) (P = 0.021). The PFS in the elderly group tended to be shorter than that in the younger group (P = 0.058, hazard ratio [HR] 1.98). The modified albumin-bilirubin (mALBI) grade (hepatic function) (HR, 2.60; P = 0.01) and objective response (HR, 0.41; P = 0.011) were independently associated with the PFS in the multivariate analysis. CONCLUSION: The management of AEs is crucial for adherence and maintaining the dose intensity of lenvatinib in elderly HCC patients.

Comparison of novel large-bore and conventional-bore covered self-expandable metal stents for malignant gastric outlet obstruction: Multicenter, retrospective study.

OBJECTIVES: Covered self-expandable metal stent (cSEMS) for gastric outlet obstruction (GOO) has been developed to overcome tumor ingrowth but is prone to be associated with an increased risk of migration. Clinical impact of the novel large-bore cSEMS for malignant GOO remains unclear. METHODS: A total of 117 patients undergoing endoscopic cSEMS placement for malignant GOO were enrolled in this multicenter retrospective study. Technical and clinical success, adverse events, recurrent GOO, and survival after stent placement were compared between 24 mm-cSEMS (n = 49) and 20 mm-cSEMS (n = 68). RESULTS: Patient characteristics were well-balanced and thus similar survival was observed between the two groups (136 days vs. 89 days, P = 0.60). Technical success rate of 100% and clinical success rate of 96% were achieved both in 24 mm-cSEMS and 20 mm-cSEMS, respectively. The median cumulative time to recurrent GOO was significantly longer in 24 mm-cSEMS than in 20 mm-cSEMS (380 days vs. 138 days, P = 0.01). The incidence of adverse events and recurrent GOO was comparable: 12% vs. 15% (P = 0.91), and 16% vs. 31% (P = 0.11); however, no stent migration was observed in 24 mm-cSEMS. In a subgroup analysis, the superiority of 24 mm-cSEMS to 20 mm-cSEMS was demonstrated in extrinsic cancers (380 days vs. 121 days, P = 0.01) but not in intrinsic cancers (151 days vs. not reached, P = 0.47). CONCLUSIONS: The 24 mm-cSEMS may improve time to recurrent GOO with ensuring acceptable safety in patients with malignant GOO.

KRAS variant allele frequency, but not mutation positivity, associates with survival of patients with pancreatic cancer.

KRAS mutation is a major driver of pancreatic carcinogenesis and will likely be a therapeutic target. Due to lack of sensitive assays for clinical samples of pancreatic cancer with low cellularity, KRAS mutations and their prognostic association have not been fully examined in large populations. In a multi-institutional cohort of 1162 pancreatic cancer patients with formalin-fixed paraffin-embedded tumor samples, we undertook droplet digital PCR (ddPCR) for KRAS codons 12/13/61. We examined detection rates of KRAS mutations by clinicopathological parameters and survival associations of KRAS mutation status. Multivariable hazard ratios (HRs) and 95% confidence intervals (CIs) for disease-free survival (DFS) and overall survival (OS) were computed using the Cox regression model with adjustment for potential confounders. KRAS mutations were detected in 1139 (98%) patients. The detection rate did not differ by age of tissue blocks, tumor cellularity, or receipt of neoadjuvant chemotherapy. KRAS mutations were not associated with DFS or OS (multivariable HR comparing KRAS-mutant to KRAS-wild-type tumors, 1.04 [95% CI, 0.62-1.75] and 1.05 [95% CI, 0.60-1.84], respectively). Among KRAS-mutant tumors, KRAS variant allele frequency (VAF) was inversely associated with DFS and OS with HRs per 20% VAF increase of 1.27 (95% CI, 1.13-1.42; ptrend <0.001) and 1.31 (95% CI, 1.16-1.48; ptrend <0.001), respectively. In summary, ddPCR detected KRAS mutations in clinical specimens of pancreatic cancer with high sensitivity irrespective of parameters potentially affecting mutation detections. KRAS VAF, but not mutation positivity, was associated with survival of pancreatic cancer patients.

HBx-induced degradation of Smc5/6 complex impairs homologous recombination-mediated repair of damaged DNA.

BACKGROUND & AIMS: HBV causes hepatocellular carcinoma (HCC). While it was recently shown that the ability of HBV X protein (HBx) to impair the Smc5/6 (structural maintenance of chromosome 5/6) complex is important for viral transcription, HBx is also a potent driver of HCC. However, the mechanism by which HBx expression induces hepatocarcinogenesis is unclear. METHODS: Degradation of the Smc5/6 complex and accumulation of DNA damage were observed in both in vivo and in vitro HBV infection models. Rescue experiments were performed using nitazoxanide (NTZ), which inhibits degradation of the Smc5/6 complex by HBx. RESULTS: HBx-triggered degradation of the Smc5/6 complex causes impaired homologous recombination (HR) repair of DNA double-strand breaks (DSBs), leading to cellular transformation. We found that DNA damage accumulated in the liver tissue of HBV-infected humanized chimeric mice, HBx-transgenic mice, and human tissues. HBx suppressed the HR repair of DSBs, including that induced by the CRISPR-Cas9 system, in an Smc5/6-dependent manner, which was rescued by restoring the Smc5/6 complex. NTZ restored HR repair in, and colony formation by, HBx-expressing cells. CONCLUSIONS: Degradation of the Smc5/6 complex by HBx increases viral transcription and promotes cellular transformation by impairing HR repair of DSBs. LAY SUMMARY: The hepatitis B virus expresses a regulatory protein called HBV X protein (or HBx). This protein degrades the Smc5/6 complex in human hepatocytes, which is essential for viral replication. We found that this process also plays a key role in the accumulation of DNA damage, which contributes to HBx-mediated tumorigenesis.