Aberrant Methylation of Somatostatin Receptor 2 Gene Is Initiated in Aged Gastric Mucosa Infected with Helicobacter pylori and Consequential Gene Silencing Is Associated with Establishment of Inflammatory Microenvironment In Vitro Study.

The loss-of-function variants are thought to be associated with inflammation in the stomach. We here aimed to evaluate the extent and role of methylation at the SSTR2 promoter in inflammation and gastric tumor formation. A whole-genome bisulfite sequencing analysis revealed that the SSTR2 promoter was significantly hypermethylated in gastric tumors, dysplasia, and intestinal metaplasia compared to non-tumor tissues from patients with gastric cancer. Using public data, we confirmed SSTR2 promoter methylation in primary gastric tumors and intestinal metaplasia, and even aged gastric mucosae infected with Helicobacter pylori, suggesting that aberrant methylation is initiated in normal gastric mucosa. The loss-of-function of SSTR2 in SNU638 cell-induced cell proliferation in vitro, while stable transfection of SSTR2 in AGS and MKN74 cells inhibited cell proliferation and tumorigenesis in vitro and in vivo. As revealed by a comparison of target genes differentially expressed in these cells with hallmark molecular signatures, inflammation-related pathways were distinctly induced in SSTR2-KO SNU638 cell. By contrast, inflammation-related pathways were inhibited in AGS and MKN74 cells ectopically expressing SSTR2. Collectively, we propose that SSTR2 silencing upon promoter methylation is initiated in aged gastric mucosae infected with H. pylori and promotes the establishment of an inflammatory microenvironment via the intrinsic pathway. These findings provide novel insights into the initiation of gastric carcinogenesis.

Dysplastic Stem Cell Plasticity Functions as a Driving Force for Neoplastic Transformation of Precancerous Gastric Mucosa.

BACKGROUND & AIMS: Dysplasia carries a high risk of cancer development; however, the cellular mechanisms for dysplasia evolution to cancer are obscure. We have previously identified 2 putative dysplastic stem cell (DSC) populations, CD44v6neg/CD133+/CD166+ (double positive [DP]) and CD44v6+/CD133+/CD166+ (triple positive [TP]), which may contribute to cellular heterogeneity of gastric dysplasia. Here, we investigated functional roles and cell plasticity of noncancerous Trop2+/CD133+/CD166+ DSCs initially developed in the transition from precancerous metaplasia to dysplasia in the stomach. METHODS: Dysplastic organoids established from active Kras-induced mouse stomachs were used for transcriptome analysis, in vitro differentiation, and in vivo tumorigenicity assessments of DSCs. Cell heterogeneity and genetic alterations during clonal evolution of DSCs were examined by next-generation sequencing. Tissue microarrays were used to identify DSCs in human dysplasia. We additionally evaluated the effect of casein kinase 1 alpha (CK1α) regulation on the DSC activities using both mouse and human dysplastic organoids. RESULTS: We identified a high similarity of molecular profiles between DP- and TP-DSCs, but more dynamic activities of DP-DSCs in differentiation and survival for maintaining dysplastic cell lineages through Wnt ligand-independent CK1α/ß-catenin signaling. Xenograft studies demonstrated that the DP-DSCs clonally evolve toward multiple types of gastric adenocarcinomas and promote cancer cell heterogeneity by acquiring additional genetic mutations and recruiting the tumor microenvironment. Last, growth and survival of both mouse and human dysplastic organoids were controlled by targeting CK1α. CONCLUSIONS: These findings indicate that the DSCs are de novo gastric cancer-initiating cells responsible for neoplastic transformation and a promising target for intervention in early induction of gastric cancer.

Predictive biomarkers for 5-fluorouracil and oxaliplatin-based chemotherapy in gastric cancers via profiling of patient-derived xenografts.

Gastric cancer (GC) is commonly treated by chemotherapy using 5-fluorouracil (5-FU) derivatives and platinum combination, but predictive biomarker remains lacking. We develop patient-derived xenografts (PDXs) from 31 GC patients and treat with a combination of 5-FU and oxaliplatin, to determine biomarkers associated with responsiveness. When the PDXs are defined as either responders or non-responders according to tumor volume change after treatment, the responsiveness of PDXs is significantly consistent with the respective clinical outcomes of the patients. An integrative genomic and transcriptomic analysis of PDXs reveals that pathways associated with cell-to-cell and cell-to-extracellular matrix interactions enriched among the non-responders in both cancer cells and the tumor microenvironment (TME). We develop a 30-gene prediction model to determine the responsiveness to 5-FU and oxaliplatin-based chemotherapy and confirm the significant poor survival outcomes among cases classified as non-responder-like in three independent GC cohorts. Our study may inform clinical decision-making when designing treatment strategies.

RUNX3 methylation drives hypoxia-induced cell proliferation and antiapoptosis in early tumorigenesis.

Inactivation of tumor suppressor Runt-related transcription factor 3 (RUNX3) plays an important role during early tumorigenesis. However, posttranslational modifications (PTM)-based mechanism for the inactivation of RUNX3 under hypoxia is still not fully understood. Here, we demonstrate a mechanism that G9a, lysine-specific methyltransferase (KMT), modulates RUNX3 through PTM under hypoxia. Hypoxia significantly increased G9a protein level and G9a interacted with RUNX3 Runt domain, which led to increased methylation of RUNX3 at K129 and K171. This methylation inactivated transactivation activity of RUNX3 by reducing interactions with CBFß and p300 cofactors, as well as reducing acetylation of RUNX3 by p300, which is involved in nucleocytoplasmic transport by importin-α1. G9a-mediated methylation of RUNX3 under hypoxia promotes cancer cell proliferation by increasing cell cycle or cell division, while suppresses immune response and apoptosis, thereby promoting tumor growth during early tumorigenesis. Our results demonstrate the molecular mechanism of RUNX3 inactivation by G9a-mediated methylation for cell proliferation and antiapoptosis under hypoxia, which can be a therapeutic or preventive target to control tumor growth during early tumorigenesis.

Prognostic Impact of Frozen Section Investigation and Extent of Proximal Safety Margin in Gastric Cancer Resection.

BACKGROUND AND AIMS: Guidelines propose different extents of macroscopic proximal margin for gastric cancer and frozen margin investigation in selected cases, but data is lacking. This study was to evaluate the necessary extent of macroscopic proximal margin, accuracy of frozen margin investigation, and prognostic impact of tumor-free proximal margin length in pT2-pT4 gastric cancer. STUDY DESIGN: Proximal and distal frozen margins were routinely investigated intraoperatively in all pT2-pT4 gastric cancers resected between 2011 and 2017. Macroscopic and microscopic proximal margin lengths were correlated. For R0-resections, survival analysis was performed for distal gastrectomy (DG) with microscopic proximal margin length ≤3 cm versus >3 cm. RESULTS: Overall, 1484 patients were included. Microscopic proximal margin lengths were macroscopically more often misestimated in diffuse histology (P = 0.0004), but extent of underestimation in centimeter was similar to intestinal and mixed/undetermined type (P = 0.134). Fifteen cases (1.0%) resulted in R1-resection, 10 at distal, and 5 at proximal margin but none with macroscopic proximal margin ≥3 cm and negative frozen section. Overall agreement of frozen margin and final pathology was 2951/2968 (99.4%). Proximal margin length in DG did not correlate with survival or recurrence in R0-resected patients. DISCUSSION: Diffuse histology is at higher risk for underestimation of proximal margin length, but extent of underestimation is similar in other Laurén subtypes. If ≥3 cm macroscopic proximal margin length is applied with intraoperative frozen margin confirmation, R1-resection can be avoided. CONCLUSION: In pT2-T4a gastric cancer, proximal margin of ≥3 cm plus frozen margin confirmation provides high oncological safety. In DG patients with R0-resection, proximal margin length does not correlate with survival or recurrence.

microRNA-30a arbitrates intestinal-type early gastric carcinogenesis by directly targeting ITGA2.

BACKGROUND: Spasmolytic polypeptide-expressing metaplasia (SPEM) is considered a precursor lesion of intestinal metaplasia and intestinal-type gastric cancer (GC), but little is known about microRNA alterations during metaplasia and GC developments. Here, we investigate miR-30a expression in gastric lesions and identify its novel target gene which is associated with the intestinal-type GC. METHODS: We conducted in situ hybridization and qRT-PCR to determine miR-30a expression in gastric tissues. miR-30a functions were determined through induction or inhibition of miR-30a in GC cell lines. A gene microarray was utilized to confirm miR-30a target genes in GC, and siRNA-mediated target gene suppression and immunostaining were performed. The Cancer Genome Atlas data were utilized to validate gene expressions. RESULTS: We found down-regulation of miR-30a during chief cell transdifferentiation into SPEM. MiR-30a level was also reduced in the early stage of GC, and its level was maintained in advanced GC. We identified a novel target gene of miR-30a and ITGA2, and our results showed that either ectopic expression of miR-30a or ITGA2 knockdown suppressed GC cell proliferation, migration, and tumorigenesis. Levels of ITGA2 inversely correlated with levels of miR-30a in human intestinal-type GC. CONCLUSION: We found down-regulation of miR-30a in preneoplastic lesions and its tumor-suppressive functions by targeting ITGA2 in GC. The level of ITGA2, which functions as an oncogene, was up-regulated in human GC. The results of this study suggest that coordination of the miR-30a-ITGA2 axis may serve as an important mechanism in the development of gastric precancerous lesions and intestinal-type GC.

Identification of a molecular signature of prognostic subtypes in diffuse-type gastric cancer.

BACKGROUND: Although recent advances in high-throughput technology have provided many insights into gastric cancer (GC), few reliable biomarkers for diffuse-type GC have been identified. Here, we aim to identify a prognostic and predictive signature of diffuse-type GC heterogeneity. METHODS: We analyzed RNA-seq-based transcriptome data to identify a molecular signature in 150 gastric tissue samples including 107 diffuse-type GCs. The predictive value of the signature was verified using other diffuse-type GC samples in three independent cohorts (n = 466). Log-rank and Cox regression analyses were used to estimate the association between the signature and prognosis. The signature was also characterized by somatic variant analyses and tissue microarray analysis between diffuse-type GC subtypes. RESULTS: Transcriptomic profiling of RNA-seq data identified a signature which revealed distinct subtypes of diffuse-type GC: the intestinal-like (INT) and core diffuse-type (COD) subtypes. The signature showed high predictability and independent clinical utility in diffuse-type GC prognosis in other patient cohorts (HR 2.058, 95% CI 1.53-2.77, P = 1.76 × 10-6). Integrative mutational and gene expression analyses demonstrated that the COD subtype was responsive to chemotherapy, whereas the INT subtype was responsive to immunotherapy with an immune checkpoint inhibitor (ICI). Tissue microarray analysis showed the practical utility of IGF1 and NXPE2 for predicting diffuse-type GC heterogeneity. CONCLUSIONS: We present a molecular signature that can identify diffuse-type GC patients who display different clinical behaviors as well as responses to chemotherapy or ICI treatment.

Nomogram for predicting gastric cancer recurrence using biomarker gene expression.

BACKGROUND: Recently, researchers have tried to predict patient prognosis using biomarker expression in cancer patients. The aim of this study was to develop a nomogram predicting the 5-year recurrence-free probability (RFP) of gastric cancer patients using prognostic biomarker gene expression. METHODS: We enrolled 360 patients in the training data set to develop the predictive model and nomogram. We analyzed the patients' general variables and the gene expression levels of 10 prognostic biomarker candidates between the nonrecurrence and recurrence groups. We also performed external validation using 420 patients from the validation data set. RESULTS: The final nomogram was composed of age, sex, and the expression levels of CAPZA, PPase, OCT-1, PRDX4, gamma-enolase, and c-Myc. The five-year RFPs were 89%, 75%, 54% and 32% for the patients in the low-risk, intermediate-risk, high-risk and very-high-risk groups in the development cohort, respectively. In the external validation cohort, the 5-year RFPs were 89%, 75%, 63% and 60%, respectively. The areas under the curve were 0.718 (95% CI, 0.65-0.78) and 0.640 (95% CI, 0.57-0.70) for the training and validation data sets, respectively. The RFP Kaplan-Meier curves were significantly different among the 4 groups in the training and validation data sets (p < 0.0001). CONCLUSION: This newly developed nomogram using gene expression can predict the 5-year RFP for gastric cancer patients after surgical treatment. We hope that this nomogram will help in the therapeutic decision between endoscopic treatment and gastrectomy.

Pylorus-preserving gastrectomy for early cancer involving the upper third: can we go higher?

BACKGROUND: Pylorus-preserving gastrectomy (PPG) is commonly performed for early gastric cancer (EGC) located in middle third of the stomach. We investigated the surgical, oncological, and functional outcomes of PPG involving the upper third of stomach. METHODS: We included all patients of the period 2013-2016 who underwent PPG, distal subtotal gastrectomy (DSG), and total gastrectomy (TG) for EGC involving the upper third by carefully defining the localization. Surgical, oncological, and functional outcome analyses included postoperative morbidity, lymph-node metastasis, tumor recurrence, postoperative body weight, body mass index, hemoglobin, total protein, albumin, quantification of intraabdominal fat, and gallstone development. RESULTS: Overall, 288 cases were analyzed: 145 PPG, 61 DSG, and 82 TG. In the study period, patients potentially underwent PPG for EGC involving the upper third, if enough proximal remnant stomach was found whilst achieving a sufficient proximal margin. PPG resulted in less operation time (p < 0.001), less blood loss (p = 0.002) and lower postoperative morbidity compared to TG. For lymph-node (LN) stations being resected in all groups, no difference was found in number of resected LN. Recurrence-free survival was similar for all groups. PPG showed advantages regarding postoperative body weight, hemoglobin, total protein, albumin in postoperative 6 and 12 month follow-up. Lowest decrease of abdominal fat area after 12 months was seen for PPG. Gallstone incidence was significantly lower after PPG compared to TG (p < 0.001). CONCLUSIONS: For EGC involving the upper third, PPG can be another good option with lower postoperative morbidity, better functional outcomes, and same oncological safety.

Alterations in the Rho pathway contribute to Epstein-Barr virus-induced lymphomagenesis in immunosuppressed environments.

Epstein-Barr virus (EBV)-positive diffuse large B-cell lymphomas (EBV+-DLBLs) tend to occur in immunocompromised patients, such as the elderly or those undergoing solid organ transplantation. The pathogenesis and genomic characteristics of EBV+-DLBLs are largely unknown because of the limited availability of human samples and lack of experimental animal models. We observed the development of 25 human EBV+-DLBLs during the engraftment of gastric adenocarcinomas into immunodeficient mice. An integrated genomic analysis of the human-derived EBV+-DLBLs revealed enrichment of mutations in Rho pathway genes, including RHPN2, and Rho pathway transcriptomic activation. Targeting the Rho pathway using a Rho-associated protein kinase (ROCK) inhibitor, fasudil, markedly decreased tumor growth in EBV+-DLBL patient-derived xenograft (PDX) models. Thus, alterations in the Rho pathway appear to contribute to EBV-induced lymphomagenesis in immunosuppressed environments.

HER2 Status in Gastric and Gastroesophageal Junction Cancer: Results of the Large, Multinational HER-EAGLE Study.

Human epidermal growth factor receptor 2 (HER2) dysregulation is associated with tumorigenesis in gastric/gastroesophageal junction cancer; however, the number of patients with HER2-positive disease is unclear, possibly due to differing scoring criteria/assays. Data are also lacking for early disease. We aimed to assess the HER2-positivity rate using approved testing criteria in a large, real-life multinational population. HER2-positivity was defined as an immunohistochemistry staining score of 3+, or immunohistochemistry 2+ and HER2 amplification detected by in situ hybridization. A total of 4949 patients were enrolled and results showed that 14.2% of 4920 samples with immunohistochemistry results were HER2-positive. HER2-positivity was significantly higher in males (16.1% vs. 9.6% in females), in gastroesophageal versus stomach tumors (22.1% vs. 12.9%), in biopsy versus surgical samples (18.3% vs. 13.0%), in intestinal tumor subtypes versus diffuse (21.5% vs. 4.8%) and mixed types (21.5% vs. 8.5%) (P<0.001), in mixed versus diffuse types (8.5% vs. 4.8%), and in "other" versus diffuse types (11.7% vs. 4.8%; P=0.002). There were no significant differences between stages. Patients in the youngest age percentile had significantly lower HER2-positivity rates than patients in the remaining percentiles (9.2% vs. 15.9%, 15.7%, and 15.1%; P<0.001). HER2-positivity was highest in France (20.2%) and lowest in Hong Kong (10.4%). In conclusion, HER-EAGLE, the first study of its kind to be conducted in a large, multinational population of almost 5000 patients, gives valuable insights into the real-world HER2-positivity rate in a gastric/gastroesophageal junction cancer patient population not selected for disease stage or histology.

Recurrence Pattern and Lymph Node Metastasis of Adenocarcinoma at the Esophagogastric Junction.

BACKGROUND: The surgical approach for adenocarcinoma of the esophagogastric junction (AEJ) still is controversial despite revised tumor-node-metastasis (TNM) classification. This study aimed to evaluate the oncologic outcome of a routine transhiatal approach for AEJ in terms of recurrence and lymph node (LN) metastasis of AEJ. METHODS: Recurrence patterns and LN metastasis of a single, primary AEJ (n = 463) treated by a surgical resection using a transhiatal approach without routine complete mediastinal LN dissection or routine splenectomy were analyzed respectively. To validate current treatment for recurrence, a validation index of recurrence (ViR; overall survival/incidence of solitary recurrence factor) was developed. RESULTS: The overall recurrence rate for AEJ was 20.3%, which did not differ significantly between AEJ II (20.8%; n = 125) and AEJ III (20.1%; n = 338). Mediastinal recurrence did not differ significantly among the subtypes of AEJ, irrespective of gastroesophageal junction involvement. Splenic hilar LN recurrence-free survival did not differ significantly between the gastrectomy-only group, the gastrectomy-plus-splenectomy group, and the gastrectomy plus distal pancreatectomy group. The solitary recurrence rate for the mediastinal LN was 0.7% for AEJ, and the overall median survival with that recurrence was 30.5 months. The ViR for mediastinal LN recurrence (43.6) was higher than for regional LN (20.9) or distant LN (14.6) metastasis. CONCLUSION: In terms of LN metastasis and recurrence, a transhiatal approach without complete mediastinal LN dissection can be acceptable, and routine splenectomy is not necessary for AEJ II or AEJ III arising within the stomach.

Gastric Carcinogenesis in the miR-222/221 Transgenic Mouse Model.

PURPOSE: MicroRNAs (miRNAs) regulate various cellular functions, including development, cell proliferation, apoptosis, and tumorigenesis. Different signatures associated with various tissue types, diagnosis, progression, prognosis, staging, and treatment response have been identified by miRNA expression profiling of human tumors. miRNAs function as oncogenes or as tumor suppressors. The relationship between gastric cancer and miRNA garnered attention due to the high incidence of gastric cancer in Asian countries. miR-222/221 expression increases in gastric tumor tissues. The oncogenic effect of miR-222/221 was previously determined in functional studies and xenograft models. In this study, transgenic mice over-expressing miR-222/221 were generated to confirm the effect of miR-222/221 on gastric carcinogenesis. MATERIALS AND METHODS: At 6 weeks of age, 65 transgenic mice and 53 wild-type mice were given drinking water containing N-nitroso-N-methylurea (MNU) for 5 alternating weeks to induce gastric cancer. The mice were euthanized at 36 weeks of age and histologic analysis was performed. RESULTS: Hyperplasia was observed in 3.77% of the wild-type mice and in 18.46% of the transgenic mice (p=0.020). Adenoma was observed in 20.75% of the wild-type mice and 26.15% of the transgenic mice (p=0.522). Carcinoma was observed in 32.08% of the wild-type mice and 41.54% of the transgenic mice (p=0.341). The frequency of hyperplasia, adenoma, and carcinoma was higher in transgenic mice, but the difference was statistically significant only in hyperplasia. CONCLUSION: These results suggest that hyperplasia, a gastric pre-cancerous lesion, is associated with miR-222/221 expression but miR-222/221 expression does not affect tumorigenesis itself.

Improvement of anti-cancer drug efficacy via thermosensitive hydrogel in peritoneal carcinomatosis in gastric cancer.

Peritoneal carcinomatosis (PC) of gastric origin has a poor prognosis with short survival due to lack of effective therapeutic modalities. Here, we evaluated the therapeutic efficacy of an injectable thermosensitive poly (organophosphazene) (PPZ) hydrogel with docetaxel (DTX-gel) to develop an effective therapeutic agent for patient with PC. Three days after inoculation of highly metastatic 44As3Luc cells into peritoneal cavity, the mice were intravenously or intraperitoneally administered with docetaxel alone (DTX-sol IV or IP), and intraperitoneally injected with DTX-gel. The anti-tumor activity was monitored by bioluminescence live imaging system. Compared to DTX-sol IV or IP, the tumor growth was significantly reduced in the DTX-gel treated mice (p<0.0001, p=0.0001). Furthermore, the survival rate was significantly increased in the DTX-gel treated mice compared to DTX-sol IV or IP treated mice (p<0.0001, p=0.0068). Our results demonstrated that DTX-gel suppresses peritoneal metastasis by continuing release of chemotherapy agent, which leads to increase the survival rate in a PC model. Therefore, biodegradable thermosensitive hydrogel with docetaxel system can be a good anti-cancer agent for PC.

Gold thread implantation promotes hair growth in human and mice.

Thread-embedding therapy has been widely applied for cosmetic purposes such as wrinkle reduction and skin tightening. Particularly, gold thread was reported to support connective tissue regeneration, but, its role in hair biology remains largely unknown due to lack of investigation. When we implanted gold thread and Happy Lift™ in human patient for facial lifting, we unexpectedly found an increase of hair regrowth in spite of no use of hair growth medications. When embedded into the depilated dorsal skin of mice, gold thread or polyglycolic acid (PGA) thread, similarly to 5% minoxidil, significantly increased the number of hair follicles on day 14 after implantation. And, hair re-growth promotion in the gold threadimplanted mice were significantly higher than that in PGA thread group on day 11 after depilation. In particular, the skin tissue of gold thread-implanted mice showed stronger PCNA staining and higher collagen density compared with control mice. These results indicate that gold thread implantation can be an effective way to promote hair re-growth although further confirmatory study is needed for more information on therapeutic mechanisms and long-term safety.

Is preoperative staging enough to guide lymph node dissection in clinically early gastric cancer?

BACKGROUND: Limited by the accuracy of preoperative staging, some cases of gastric cancer invading the muscularis propria (pT2) are underestimated as early gastric cancer (EGC) in the preoperative assessment. The aim of this present study was to determine prognostic factors and to propose indications for limited lymph node dissection in patients with clinically EGC (cEGC). METHODS: Patients of cEGC (n = 2072) who were postoperatively diagnosed as pT1 (cT1pT1, n = 1858) and pT2 (cT1pT2, n = 214) from 2005 to 2009 at Seoul National University Hospital were retrospectively analyzed. RESULTS: There was no difference in 5-year survival rate between the cT1pT1 and cT1pT2 group (95.5 % vs. 92.5 %, P = 0.059), and both groups had better overall survival than pT2 patients who were preoperatively diagnosed as locally advanced gastric cancer (cT2-4pT2), whose 5-year survival rate was 78.0 % (P < 0.001). Multivariate analysis indicated lymph node metastasis (LNM) was the independent prognostic factor for cEGC (P < 0.001). In cEGC patients, three preoperative factors, including N stage by multidetector-row computed tomography (MDCT) (P < 0.001), preoperative histological type (P < 0.001), and tumor size (P < 0.001), were associated with LNM by multivariate analysis. Regarding the possibility of LNM, low-risk (4.4 %) and high-risk (17.3 %) groups were developed based on weighted scores of the aforementioned independent three variables. Among 52 patients in the low-risk group, the extension of LNM was limited to the perigastric area. CONCLUSIONS: Comprehensive evaluation based on MDCT, preoperative histological type, and tumor size is an effective method to predict LNM and guide tailored LN dissection for cEGC.

TMBIM6 (transmembrane BAX inhibitor motif containing 6) enhances autophagy and reduces renal dysfunction in a cyclosporine A-induced nephrotoxicity model.

Cyclosporine A (CsA) is widely used as an immunosuppressor in transplantation. Previous studies reported that CsA induces autophagy and that chronic treatment with CsA results in accumulation of autophagosomes and reduced autophagic clearance. Autophagy is a prosurvival process that promotes recovery from acute kidney injury by degrading misfolded proteins produced in the kidney. In the present study, we used TMBIM6-expressing HK-2, human kidney tubular cells (TMBIM6 cells) and Tmbim6 knockout (tmbim6(-/-)) mice. When exposed to CsA, the TMBIM6 cells maintained autophagy activity by preventing autophagosome accumulation. With regard to signaling, PRKKA/AMPK phosphorylation and mechanistic target of rapamycin (serine/threonine kinase) complex 1 (MTORC1) expression and its downstream target TFEB (transcription factor EB), a lysosome biogenesis factor, were regulated in the TMBIM6 cells. Lysosomal activity was highly increased or stably maintained in the presence of TMBIM6. In addition, treatment of tmbim6(-/-) mice with CsA resulted in increased autophagosome formation and decreased lysosome formation and activity. We also found that tmbim6(-/-) mice were susceptible to CsA-induced kidney injury. Taken together, these results indicate that TMBIM6 protects against CsA-induced nephrotoxicity both in vitro and in vivo by inducing autophagy and activating lysosomes.

Comparison of Surgical Outcomes of Robot-Assisted and Laparoscopy-Assisted Pylorus-Preserving Gastrectomy for Gastric Cancer: A Propensity Score Matching Analysis.

BACKGROUND: The three-dimensional view and articulating devices in robot system might have a benefit performing the delicate procedure of pylorus-preserving gastrectomy. This study was conducted to evaluate the feasibility and safety of robot-assisted pylorus-preserving gastrectomy (RAPPG) and to compare the perioperative outcomes and oncologic safety between RAPPG and laparoscopy-assisted pylorus-preserving gastrectomy (LAPPG) for middle-third early gastric cancer. METHODS: Between June 2008 and December 2013, we retrospectively collected data of 68 patients with RAPPG and propensity score matched 68 patients with LAPPG for the treatment of early gastric cancer at Seoul National University Hospital. The covariates for propensity score matching were: age, sex, American Society of Anesthesiologists score, body mass index, and operators. Clinicopathologic characteristics and surgical outcomes were compared between the two groups. RESULTS: All RAPPG cases were performed successfully without open or laparoscopic conversion. Patient demographics and perioperative outcomes did not differ between the two groups except in operation time (258.3 vs. 193.9 min; P < 0.001). There was no significant difference in complication rates between the two groups (19.1 vs. 22.1 %; P = 0.671). The mean number of examined lymph nodes (33.4 vs. 36.5; P = 0.153), and the mean number of lymph nodes at each station was not different between the two groups. CONCLUSIONS: RAPPG can be a safe treatment option for middle-third early gastric cancer in terms of surgical complications and oncologic outcomes. However, RAPPG has no benefit over LAPPG in this study.

Human epidermal growth factor receptor 2 testing in gastric cancer: recommendations of an Asia-Pacific task force.

Human epidermal growth factor receptor 2 (HER2) testing in gastric and gastroesophageal junction cancer is an evolving area in clinical practice that has particular relevance to Asia-Pacific countries, which face a high incidence of these diseases. A growing body of evidence demonstrates that HER2-targeted therapy improves survival for patients with HER2-positive advanced disease, and drives the need for high-quality testing procedures to identify patients who will respond to treatment. However, various factors challenge day-to-day testing of gastric specimens in these countries, to a degree greater than that observed for breast specimens. Recommendations for HER2 testing of gastric cancer specimens were published as a result of the Trastuzumab for Gastric Cancer (ToGA) trial. The guidelines proposed in this manuscript build on these recommendations and emphasize local testing environments, particularly in Asia-Pacific countries. A multidisciplinary task force comprising experts from Asia-Pacific who actively work and provide education in the area was convened to assess the applicability of existing recommendations in the Asia-Pacific region. The resulting recommendations reported here highlight and clarify aspects of testing that are of particular relevance to the region, and notably emphasize multidisciplinary collaborations to optimize HER2 testing quality.

Large-scale characterization of DNA methylation changes in human gastric carcinomas with and without metastasis.

PURPOSE: Metastasis is the leading cause of death for gastric carcinoma. An epigenetic biomarker panel for predicting gastric carcinoma metastasis could have significant clinical impact on the care of patients with gastric carcinoma. The main purpose of this study is to characterize the methylation differences between gastric carcinomas with and without metastasis. EXPERIMENTAL DESIGN: Genome-wide DNA methylation profiles between 4 metastatic and 4 nonmetastatic gastric carcinomas and their surgical margins (SM) were analyzed using methylated-CpG island amplification with microarray. The methylation states of 73 candidate genes were further analyzed in patients with gastric carcinoma in a discovery cohort (n=108) using denatured high performance liquid chromatography, bisulfite-sequencing, and MethyLight. The predictive values of potential metastasis-methylation biomarkers were validated in cohorts of patients with gastric carcinoma in China (n=330), Japan (n=129), and Korea (n=153). RESULTS: The gastric carcinoma genome showed significantly higher proportions of hypomethylation in the promoter and exon-1 regions, as well as increased hypermethylation of intragenic fragments when compared with SMs. Significant differential methylation was validated in the CpG islands of 15 genes (P<0.05) and confirmed using bisulfite sequencing. These genes included BMP3, BNIP3, CDKN2A, ECEL1, ELK1, GFRA1, HOXD10, KCNH1, PSMD10, PTPRT, SIGIRR, SRF, TBX5, TFPI2, and ZNF382. Methylation changes of GFRA1, SRF, and ZNF382 resulted in up- or downregulation of their transcription. Most importantly, the prevalence of GFRA1, SRF, and ZNF382 methylation alterations was consistently and coordinately associated with gastric carcinoma metastasis and the patients' overall survival throughout discovery and validation cohorts in China, Japan, and Korea. CONCLUSION: Methylation changes of GFRA1, SRF, and ZNF382 may be a potential biomarker set for prediction of gastric carcinoma metastasis.