A minute primary gastric synovial sarcoma with ulcer: a case report.

BACKGROUND: Synovial sarcomas are a rare type of high-grade sarcomas with unknown cell origin. They arise predominantly in the soft tissues but rarely in the stomach. We recently encountered a rare case of minute gastric synovial sarcoma. CASE PRESENTATION: A 61-year-old Japanese woman was pointed out edematous erosion at the body of the stomach. Biopsy specimen showed dense proliferation of spindle-shaped tumor cells mixed with smooth muscle fibers of the muscularis mucosae. Although the definite histological diagnosis was undetermined, the patient underwent laparoscopic wedge resection of the stomach. Histological examination of the resected sample revealed that the maximum diameter of the tumor was only 6 mm and that dense proliferation of rather uniform spindle tumor cells were observed mainly in the submucosa. Immunohistochemistry showed that they were positive for pan-keratin, CD99 and TLE1. SS18-SSX fusion-specific antibody gave diffuse positive staining to the tumor cells, and analysis using mRNA extracted from paraffin sections revealed that the tumor had SS18-SSX1 fusion gene. Thus, it was diagnosed as gastric synovial sarcoma, monophasic fibrous type. CONCLUSIONS: Primary synovial sarcoma of the stomach is rare and only 47 cases have been reported in the English literature to date. The maximum diameter of the lesion of our case was 6 mm which is the smallest among them.

Influences of lncRNA HEIH and DKK3 on the clinical features and prognosis of gastric cancer.

PURPOSE: To detect differential expressions of HEIH and DKK3 in gastric cancer (GC) samples, and to elucidate their influences on clinical features and disease prognosis. METHODS: The expression levels of HEIH and DKK3 in GC tissues and adjacent normal ones (>5 cm) were detected by qRT-PCR. Correlation between HEIH and DKK3 levels in GC tissues was analyzed by Pearson's correlation analysis. Sensitivity and specificity of detecting HEIH and DKK3 levels in diagnosing GC were assessed by reactive oxygen species (ROC). 5-year survival in each patient was followed up. Risk factors of prognosis in GC patients were examined by Cox regression model. RESULTS: HEIH was upregulated, and DKK3 was downregulated in GC tissues, displaying a negative correlation. Both HEIH and DKK3 were correlated to tumor diameter, lymph node metastasis and TNM staging. Combined detection of HEIH and DKK3 levels showed high specificity and sensitivity in the diagnosis of GC. Tumor diameter, lymph node metastasis, TNM staging, HEIH and DKK3 levels were independent risk factors for the prognosis of GC. CONCLUSION: The upregulated HEIH and downregulated DKK3 in GC samples showed a negative correlation between each other. HEIH and DKK3 levels were closely linked to tumor diameter, lymph node metastasis and TNM staging in GC patients. These are promising biomarkers for predicting the prognosis of GC.

Clinical and pathological significance of proliferation index and p53 expression in gastric adenocarcinoma.

PURPOSE: The purpose of our work was to investigate the association between proliferative index [proIDX] and expression index p53 (p53IDX) with the clinical and pathological characteristics of gastric adenocarcinoma. METHODS: The biopsy material of 90 patients operated on for gastric cancer was routinely processed in paraffin and archived. After the histopathological report was made, two study groups were formed, the first group (n=45) comprised biopsies with intestinal carcinoma and the second (n=45) biopsies of diffuse gastric cancer. In both cases, the control group consisted of biopsies of surrounding non-tumor tissue The routine Hematoxylin-Eosin and immunohistochemical ABC method with anti-Ki67 and anti-p53 antibodies was applied at sections 3-5 µm thick. The expression of Ki67 and p53 was quantified stereometrically. For statistical analysis SPSS (19.0) was used. RESULTS: Significantly higher Ki67 expression was found in both types of adenocarcinoma compared to the control group, as well as significant association of proIDX with most of testing parameters. Expression of p53 was significantly higher in the intestinal type compared to the diffuse type and the control group and was significantly associated with age and histological grade. Diffuse type particulary showed, significant association of p53IDX with most of the histological parameters tested. CONCLUSION: Our results point a highly significant correlation of the Ki67 and p53 expression with indicators of gastric adenocarcinoma progression, which may help to identify patients with an aggressive gastric adenocarcinoma phenotype.

Computational design and experimental substantiation of conformationally constrained peptides from the complex interfaces of transcriptional enhanced associate domains with their cofactors in gastric cancer.

Transcriptional enhanced associate domains (Teads) are the downstream effectors of the hippo signaling pathway and have been recognized as attractive druggable targets of gastric cancer. The biological function of Teads is regulated by diverse cofactors. In this study, the intermolecular interactions of Teads with their cognate cofactors were systematically characterized at structural, thermodynamic and dynamic levels. The Teads possess a double-stranded helical hairpin that is surrounded by three independent structural elements ß-sheet, α-helix and Ω-loop of cofactor proteins and plays a central role in recognition and association with cofactors. A number of functional peptides were split from the hairpin region at Tead-cofactor complex interfaces, which, however, cannot maintain in native conformation without the support of protein context and would therefore incur a considerable entropy penalty upon competitively rebinding to the interfaces. Here, we further used disulfide and hydrocarbon bridges to cyclize and staple the hairpin and helical peptides, respectively. The chemical modification strategies were demonstrated to effectively constrain peptide conformation into active state and to largely reduce peptide flexibility in free state, thus considerably improving their affinity. Since the cyclization and stapling only minimize the indirect entropy cost but do not influence the direct enthalpy effect upon peptide binding, the designed conformationally constrained peptides can retain in their native selectivity over different cofactors. This is particularly interesting because it means that the cyclized/stapled, affinity-improved peptides can specifically compete with their parent Teads for the cofactor arrays as they share consistent target specificity.

Efficacy of trastuzumab and potential risk factors on survival in patients with HER2-positive metastatic gastric cancer.

Aim: To evaluate the efficacy of trastuzumab and potential risk factors on survival in patients with HER2-positive metastatic gastric cancer. Methods: We retrospectively included 138 patients who were given trastuzumab-based chemotherapy as first-line treatment and analyzed the relationship between clinical response rates and maintenance treatment status and survival outcomes. Results: In the whole group, the median progression-free survival and overall survival were 10.2 and 16 months, respectively. Clinical response was obtained in 79% of patients. The median overall survival was 16.9 months in follow-up group and 19.0 months in the maintenance group in patients with clinical response. Continuation of maintenance trastuzumab created a significant survival advantage (p = 0.021). Eastern Cooperative Oncology Group performance status 2 (hazard ratio [HR]: 2.02), grade 3 (HR: 1.78) and more than four metastatic lesions (HR: 1.67) were determined as risk factors for death. Conclusion: We recommend the continuation of maintenance trastuzumab in patients with clinical response, but those with identified risk factors may not benefit from treatment because life expectancy may be low.

Gastric cancer has a poor prognosis despite available treatments. Inclusive studies are still needed with real-life data. Our research retrospectively evaluated the efficacy of trastuzumab and potential risk factors on survival in patients with HER2-positive metastatic gastric cancer who received trastuzumab-based chemotherapy as first-line therapy. In total, 138 patients were included in this study. Clinical response to trastuzumab-based chemotherapy was obtained in 79% of the patients. We also divided the patients who had a clinical response into two groups according to whether they received maintenance therapy. In the present study, trastuzumab administration had compatible survival outcomes with recent studies. Continuation of trastuzumab maintenance treatment provided a survival advantage in patients with clinical response. We suppose that maintenance trastuzumab may be recommended in patients with clinical responses to the first-line treatment. Furthermore, Eastern Cooperative Oncology Group Performance Status 2, grade 3 and having more than four metastatic lesions were determined as risk factors for death. Therefore, although we recommend maintenance of trastuzumab in patients with clinical response, those with identified risk factors may not benefit from treatment.

Combination of trastuzumab and taxane-containing intensified chemotherapy in first-line treatment of HER2-positive advanced gastric cancer.

PURPOSE: Taxane-containing combinations are recommended for the first-line therapy of advanced gastric cancer. It is not known which chemotherapy regimen is the best with trastuzumab for HER2-positive patients. The aim of this study was to compare taxane-containing intensified chemotherapy versus standard chemotherapy in combination with trastuzumab in the first-line treatment of HER2-positive advanced gastric adenocarcinoma. METHODS: This study is a retrospective multicenter study of the Turkish Oncology Group. A total of 130 HER2-positive patients with inoperable locally advanced, recurrent, or metastatic gastric adenocarcinoma being given chemotherapy plus trastuzumab as the first-line treatment were included from 16 different oncology centers. Trastuzumab combination with intensified chemotherapy including taxane or standard chemotherapy was compared in terms of progression-free survival (PFS), overall survival (OS), and toxicity. RESULTS: There were 108 patients in the standard and 22 patients in the intensified chemotherapy group. PFS of the standard and intensified group were 5.6 months (95% confidence interval [CI] 4.8-6.4) and 5.3 months (95% CI 2.6-8), respectively (p = 0.70). OS of the standard and intensified group were 11.1 months (95% CI 8.3-13.9) and 15.2 months (95% CI 12.7-17.7), respectively (p = 0.03). Repeated analysis excluding patients given any previous therapy revealed similar results. The intensified group had more fever and febrile neutropenia. CONCLUSION: Trastuzumab combination with intensified chemotherapy provides better OS in first-line treatment of HER2-positive advanced gastric cancer. Further large-scale studies should be performed in HER2-positive patients.

Relationship between HER2 expression and tumor interstitial angiogenesis in primary gastric cancer and its effect on prognosis.

INTRODUCTION: Her2-positive gastric cancer is a unique subtype of disease, requiring different diagnosis and treatment strategies and methods. Neoplasms are significantly correlated with the occurrence, invasion and metastasis of tumors. The purpose of this study was to explore the correlation between HER2 amplification and tumor interstitial angiogenesis in patients with gastric cancer. METHODS: The data of 1121 patients with gastric cancer were retrospectively analyzed, and the amplification of HER2 was detected by immunohistochemistry (IHC) and FISH. CD34 IHC was used to label MVD. We analyzed the factors affecting HER2 amplification, the difference in MVD under different HER2 states, the factors related to 5-year survival rate of patients, and predicted the independent factors affecting 5-year survival rate of gastric cancer patients. RESULTS: We found 115 cases with HER2 positive rate of 10.26 %. HER2 amplification was more likely in gastric cancer patients with more than 5.2 cm tumor diameter, Lauren intestinal type, tubular adenocarcinoma, and the depth of infiltration at stage T2, (P < 0.05). Gender, age, tumor location, number of lymph node metastasis, distant metastasis, clinical stage, nerve invasion and vascular tumor thrombi were not the factors affecting HER2 amplification of gastric cancer (P > 0.05). MVD count of HER2-positive gastric cancer was significantly higher than that of HER2-negative gastric cancer, (P < 0.05). The 5-year overall survival rate of 1121 patients with gastric cancer was 51.92 %. HER2 amplification, high MVD count, large tumor size, tubular adenocarcinoma, Lauren intestinal type, deep tumor infiltration, numerous lymph node metastases and late clinical stage are all associated with low 5-year survival rate, indicating poor prognosis in gastric cancer patients, (P < 0.05). The 5-year survival rate of gastric cancer patients was not correlated with gender, age, tumor location, distant metastasis, nerve invasion and vascular cancer plug, (P > 0.05). Multivariate analysis showed that Lauren classification, Infiltrating depth, Nodal status, Clinical stage, HER2 expression, MVD count were independent factors affecting the prognosis of gastric cancer patients, (P < 0.05). CONCLUSION: HER2 overexpression was not only closely related to gastric cancer neovascularization, but also an independent predictor of prognosis of gastric cancer. In clinical treatment, anti-HER2 targeted therapy and anti-angiogenesis drugs can be adopted to achieve effective treatment.

EGFR amplification and outcome in a randomised phase III trial of chemotherapy alone or chemotherapy plus panitumumab for advanced gastro-oesophageal cancers.

OBJECTIVE: Epidermal growth factor receptor (EGFR) inhibition may be effective in biomarker-selected populations of advanced gastro-oesophageal adenocarcinoma (aGEA) patients. Here, we tested the association between outcome and EGFR copy number (CN) in pretreatment tissue and plasma cell-free DNA (cfDNA) of patients enrolled in a randomised first-line phase III clinical trial of chemotherapy or chemotherapy plus the anti-EGFR monoclonal antibody panitumumab in aGEA (NCT00824785). DESIGN: EGFR CN by either fluorescence in situ hybridisation (n=114) or digital-droplet PCR in tissues (n=250) and plasma cfDNAs (n=354) was available for 474 (86%) patients in the intention-to-treat (ITT) population. Tissue and plasma low-pass whole-genome sequencing was used to screen for coamplifications in receptor tyrosine kinases. Interaction between chemotherapy and EGFR inhibitors was modelled in patient-derived organoids (PDOs) from aGEA patients. RESULTS: EGFR amplification in cfDNA correlated with poor survival in the ITT population and similar trends were observed when the analysis was conducted in tissue and plasma by treatment arm. EGFR inhibition in combination with chemotherapy did not correlate with improved survival, even in patients with significant EGFR CN gains. Addition of anti-EGFR inhibitors to the chemotherapy agent epirubicin in PDOs, resulted in a paradoxical increase in viability and accelerated progression through the cell cycle, associated with p21 and cyclin B1 downregulation and cyclin E1 upregulation, selectively in organoids from EGFR-amplified aGEA. CONCLUSION: EGFR CN can be accurately measured in tissue and liquid biopsies and may be used for the selection of aGEA patients. EGFR inhibitors may antagonise the antitumour effect of anthracyclines with important implications for the design of future combinatorial trials.

Two updates on oesophagogastric junction adenocarcinoma from the fifth WHO classification: Alteration of definition and emphasis on HER2 test.

INTRODUCTION: The incidence of oesophagogastric junction adenocarcinoma has increased rapidly but remains controversial over the last decades. There are two crucial updates of the fifth World Health Organization (WHO) classification, including the alteration of its definition and the emphasis on the human epidermal growth factor receptor 2 (HER2) test. METHODS: A total of 566 clinicopathological samples from patients who were diagnosed with gastric adenocarcinoma were retrospectively analyzed. We comprehensively compared the clinicopathological features of oesophagogastric junction adenocarcinoma between the fourth (V4.0) and fifth (V5.0) WHO versions. The clinicalpathological features among oesophagogastric junction, proximal and distal gastric tumors with fourth and fifth edition were also compared, respectively. Also, we discuss the correlation of HER2-expression with clinicopathological features according to the V5.0. RESULTS: The results showed that the difference was mainly between oesophagogastric junction and distal adenocarcinoma in V4.0, while some were found between proximal and distal adenocarcinoma in V5.0. Tumors invading the oesophagus more than 3cm were still mainly oesophagogastric junction tumors. The expression of HER2 in oesophagogastric junction and proximal gastric adenocarcinoma was still higher than that in gastric body and distal sites. CONCLUSIONS: The clinicopathological parameters of the oesophagogastric junction tumors changed to some extent in the updated WHO version. The proximal gastric tumors tended to be more invasive, more than those located in oesophagogastric junction. But the latter with oesophageal invasion required additional management. The HER2-expression of oesophagogastric junction adenocarcinoma is the highest. The classification of V5.0 is reasonable and worth recommendation.

p53 immunostaining cannot be used to predict TP53 mutations in gastric cancer: results from a large Central European cohort.

Four molecular subgroups of gastric cancer (GC) have been proposed, ie, Epstein-Barr virus (EBV)-positive, microsatellite instable, chromosomal instable (CIN), and genomically stable GC. Based on the complex relationship between chromosomal instability and TP53 mutational status, we hypothesized that the typical clinicopathological characteristics caused by chromosomal instability are correlated with the p53 expression that is detected by immunohistochemistry. Four hundred sixty-seven whole-tissue sections of patients with therapy-naive GC were stained with anti-p53 antibody. The histoscore and staining pattern were analyzed for each slide. Different algorithms of immunohistochemistry evaluation were formed and correlated with clinicopathological characteristics. The algorithms were validated by assessing the mutational status of TP53 in 111 cases. Four hundred forty-two GCs were p53 positive, and 25 were negative, including 414 GCs with a homogeneous pattern and 53 GCs with a heterogeneous staining pattern. There was no correlation with overall or tumor-specific survival. In comparison with clinicopathological characteristics, the algorithm high versus low showed correlations with microsatellite instability, hepatocyte growth factor receptor (MET), and TP53 mutational status. The algorithm Q1/Q4 versus Q2/Q3 appeared to be correlated with the phenotype as per the Laurén classification, microsatellite instability, EBV status, and p53 expression pattern. The algorithm <90% = 0 and <50% = 3+ versus ≥90% = 0 or ≥50% = 3+ showed correlations with the EBV status, microsatellite instability, grading, and p53 expression pattern. The algorithm homogeneous versus heterogeneous did not correlate with any clinicopathological characteristic. Our results showed that the immunohistochemistry of p53, TP53 mutational status, and CIN subtype were connected. However, different algorithms for p53 immunohistochemical evaluation cannot be used to predict TP53 mutations in CIN GCs in individual cases.

Claudin-18 as a Marker for Identifying the Stomach and Pancreatobiliary Tract as the Primary Sites of Metastatic Adenocarcinoma.

Identification of the primary site of cancer is essential for the treatment of patients with cancer. Numerous immunohistochemical markers have been developed to determine the differentiation of tumor cells and suggest possible primary sites, but markers of gastric and pancreatic adenocarcinomas are still lacking. Claudin-18 is a tight-junction protein uniquely expressed in gastric epithelial cells and has been shown to be expressed in gastric and pancreatic adenocarcinoma. Whether claudin-18 can be used as a marker for identifying the primary site of cancer is still unclear. In this study, we used the immunohistochemical method to stain claudin-18 in tissue arrays containing 575 carcinomas from different anatomic sites and representative sections of 157 metastatic adenocarcinomas. In the group of primary tumors, claudin-18 was frequently expressed in gastric, pancreatic, and pulmonary mucinous adenocarcinomas. Half of cholangiocarcinomas and ovarian mucinous carcinomas and some colorectal and pulmonary adenocarcinomas were also positive for claudin-18. In the metastatic cohort, 15 of 17 (88%) gastric adenocarcinomas, 18 of 23 (78%) pancreatic adenocarcinomas, and 4 of 7 (57%) cholangiocarcinomas and gallbladder adenocarcinomas were positive for claudin-18. Only 4 tumors that originated outside the stomach and pancreatobiliary tract were positive for claudin-18. After normalization to the tumor frequency, the sensitivity of claudin-18 for identifying the stomach and pancreatobiliary tract as primary tumor sites was 79%, and the specificity was 93%. The positive and negative predictive values were 76% and 94%, respectively. In conclusion, claudin-18 represents a sensitive and specific marker for stomach and pancreatobiliary adenocarcinoma that may be a useful diagnostic tool in routine surgical pathology.

Histopathologic Analysis of Signet-ring Cell Carcinoma In Situ in Patients With Hereditary Diffuse Gastric Cancer.

Hereditary diffuse gastric cancer (HDGC) is a rare autosomal dominant syndrome associated with an increased risk of developing Laurén's diffuse-type gastric carcinoma and lobular breast carcinoma. Although signet-ring cell carcinoma (SRCC) in situ (SRCC-pTis) has been reported as a characteristic lesion in HDGC cases with CDH1 germline mutations (CDH1 pathogenic variant), and a precursor of conventional intramucosal SRCC (SRCC-pT1a), its histopathologic features and specificity have not been sufficiently clarified. Here, we examined gastrectomy samples from 6 Japanese HDGC patients with CDH1 germline mutation, belonging to 4 families, and analyzed SRCC lesions histologically and immunohistochemically. Of the 274 foci found in the 6 samples, SRCC-pT1a accounted for 225 lesions (range: 8 to 107, mean 45.7 lesions per patient), while 46 foci were of SRCC-pTis (range: 1 to 15, mean 7.67 foci per patient). All SRCC-pTis foci were observed in the fundic gland area and on the superficial side of the mucosa. Histologically, tumor cells of SRCC-pTis were found between normal foveolar epithelial cells and the basement membrane, following a typical pagetoid spread pattern. Immunohistochemically, E-cadherin expression was lost in SRCC-pTis (27/28, 96.4%) more frequently than in SRCC-pT1a (95/197, 48.2%; P<0.001). To elucidate the specificity of SRCC-pTis for HDGC, 60 samples (range: 0.12 to 1.49 m, total 28.8 m of mucosal length) from gastric cancer cases were analyzed as controls, in which no SRCC-pTis were identified. Our results indicate that SRCC-pTis is a distinct histologic feature with high specificity for HDGC cases with CDH1 germline mutations.

An Integrative Morphomolecular Classification System of Gastric Carcinoma With Distinct Clinical Outcomes.

A robust morphomolecular classification system for gastric carcinoma is required. A 4-tier morphologic classification is proposed, including diffuse, intestinal, tubular, and lymphoid types. A tissue microarray for mismatch repair immunohistochemistry and Epstein-Barr virus (EBV) in situ hybridization were performed in 329 gastric carcinomas. DNA flow cytometry was used to detect aneuploidy in formalin-fixed paraffin-embedded samples. Lymphoid histology was the third most common histologic pattern at our institute and strongly associated with EBV infection and PMS2/MLH1-deficiency (both P<0.001). HER2 overexpression and SATB2 expression more frequently occurred in intestinal histology (both P<0.001). Loss of ARID1A expression was strikingly associated with lymphoid histology (P<0.001) and negative E-cadherin expression was correlated with diffuse histology (P=0.001). Programmed death-ligand 1 expression was most frequently present in lymphoid-type gastric carcinoma than other histologic subtypes and correlated with the molecular features of PMS2/MLH1-deficiency and EBV infection (all P<0.001). Aneuploidy was detected in 53% of gastric carcinomas and was highly correlated with intestinal type and the least with the lymphoid type (P<0.001). Notably, lymphoid-type gastric carcinoma showed the best outcome, whereas tubular type showed the worst survival rate (P<0.001). We integrated aneuploidy with morphologic patterns to propose a morphomolecular classification scheme, which served as a successful and independent prognostic factor in multivariate 5-year disease-free survival analysis (P<0.001). Overall, we describe an integrated morphomolecular classification system for gastric carcinomas to effectively predict patient outcomes. This system is cost-effective and reliable and can help select target therapeutics and facilitate clinical management.

Hypothesis-free deep survival learning applied to the tumour microenvironment in gastric cancer.

The biological complexity reflected in histology images requires advanced approaches for unbiased prognostication. Machine learning and particularly deep learning methods are increasingly applied in the field of digital pathology. In this study, we propose new ways to predict risk for cancer-specific death from digital images of immunohistochemically (IHC) stained tissue microarrays (TMAs). Specifically, we evaluated a cohort of 248 gastric cancer patients using convolutional neural networks (CNNs) in an end-to-end weakly supervised scheme independent of subjective pathologist input. To account for the time-to-event characteristic of the outcome data, we developed new survival models to guide the network training. In addition to the standard H&E staining, we investigated the prognostic value of a panel of immune cell markers (CD8, CD20, CD68) and a proliferation marker (Ki67). Our CNN-derived risk scores provided additional prognostic value when compared to the gold standard prognostic tool TNM stage. The CNN-derived risk scores were also shown to be superior when systematically compared to cell density measurements or a CNN score derived from binary 5-year survival classification, which ignores time-to-event. To better understand the underlying biological mechanisms, we qualitatively investigated risk heat maps for each marker which visualised the network output. We identified patterns of biological interest that were related to low risk of cancer-specific death such as the presence of B-cell predominated clusters and Ki67 positive sub-regions and showed that the corresponding risk scores had prognostic value in multivariate Cox regression analyses (Ki67&CD20 risks: hazard ratio (HR) = 1.47, 95% confidence interval (CI) = 1.15-1.89, p = 0.002; CD20&CD68 risks: HR = 1.33, 95% CI = 1.07-1.67, p = 0.009). Our study demonstrates the potential additional value that deep learning in combination with a panel of IHC markers can bring to the field of precision oncology.

Maintenance treatment in advanced HER2-negative gastric cancer.

Survival for patients with advanced gastric cancer (GC) remains poor. Systemic chemotherapy which has reached a plateau stays the standard first-line (1L) treatment for advanced human epidermal growth-factor receptor 2 (HER2)-negative GC. To maximize the benefit of 1L treatment, the concept of maintenance treatment is constantly being explored. In advanced HER2-negative GC, current clinical guidelines do not recommend a standard maintenance therapy strategy. In addition to the monotherapy maintenance with fluorouracil after 4-6 cycles of 1L chemotherapy, some agents that are active against novel targets have been evaluated in clinical trials for maintenance treatment. Whereas most of these trials do not reach their primary endpoints, they open new horizons for the 1L treatment of advanced HER2-negative GC. Therefore, we reviewed the clinical trials in the field of maintenance treatment in advanced HER2-negative GC and discussed some of the problems in clinical trials.

miR193b Promotes Apoptosis of Gastric Cancer Cells via Directly Mediating the Akt Pathway.

Gastric cancer (GC) is one of the most common and fatal malignancies worldwide. MicroRNAs (miRNAs) play a critical role in tumor initiation, proliferation, and metastasis of gastric cancer. miR193b has been identified as a tumor suppressor in a variety of tumor types; however, its role in gastric cancer is yet to be determined. Here, we found a significant downregulation of miR193b expression in both human gastric cancer tissues (p < 0.05) and human gastric cancer cell lines (p < 0.01). Furthermore, the expression level of miR193b correlated with the tumor type, tumor size, and clinical stage (p < 0.05). In vitro, miR193b overexpression inhibited cell survival and induced apoptosis in GC cell lines, indicating that miR193b plays a role in the development of gastric cancer. KRAS was verified as the target of miR193b, and KRAS overexpression attenuated miR193b-induced apoptosis (p < 0.05). Moreover, we found that the Akt pathway negatively regulated miR193b, also affecting apoptosis. Further analyses indicated that PIK3CA mutation and KRAS amplification are two mutually exclusive pathways (p < 0.01), and we hypothesize that both two pathways could result in the carcinogenic overactivation of KRAS. Thus, our results suggest that the Akt-miR193b-KRAS axis may act as a mechanism affecting apoptosis in gastric cancer cells.

AKNA Is a Potential Prognostic Biomarker in Gastric Cancer and Function as a Tumor Suppressor by Modulating EMT-Related Pathways.

The AT-hook transcription factor, AKNA, is a nuclear protein that affects a few physiological and pathological processes including cancer. Here, we investigated the role of AKNA in gastric cancer (GC). By using quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot assays, AKNA was found deregulated in both GC cell lines and 32 paired GC tissues. Subsequently, Kaplan-Meier analysis and clinicopathological analysis were conducted using both 32 GC cases' data above and RNA-Seq data of AKNA in 354 GC patients and the corresponding clinical-pathological data obtained from The Cancer Genome Atlas (TCGA), and AKNA expression was found closely related to location, metastasis, and TNM staging of GC. Then, the potential molecular mechanisms of AKNA in GC were explored by gene set enrichment analysis (GSEA), qRT-PCR, and Western blot assays. AKNA was found to be a hub gene related to homotypic cell to cell adhesion, regulation of cell to cell adhesion, leukocyte cell to cell adhesion, and regulation of T cell proliferation in GC. GO analysis revealed that AKNA involved in the regulation of epithelial-mesenchymal transition (EMT)-related pathways including chemokine signaling pathway, cytokine to cytokine receptor interaction, cell adhesion molecules, and jak-stat signaling pathway in GC. To explore the regulation of AKNA expression, Targetscan and TargetMiner were used to predict the possible miRNA which targeted AKNA and found the expression of AKNA was negatively correlated to miR-762 which could be sponged by circTRNC18. In conclusion, AKNA could function as a tumor suppressor by modulating EMT-related pathways in GC. The expression of AKNA might be regulated by circTRNC18/miR-762 axis. AKNA could serve as a potential biomarker and an effective target for GC diagnosis and therapy.

Identification of UAP1L1 as tumor promotor in gastric cancer through regulation of CDK6.

Gastric cancer (GC) is one of the most commonly diagnosed malignancies in digestive tract and its underlying molecular mechanism is still not clear, so we aimed to reveal the relationship between GC and UDP-GlcNAc pyrophosphorylase-1 like 1 (UAP1L1). The detection of UAP1L1 expression in GC tumor and normal tissues was accomplished by immunohistochemistry and demonstrated the upregulation of UAP1L1 in GC, which was statistically associated with tumor grade. GC cell models constructed via transfection of UAP1L1-silencing/overexpressing lentiviruses were employed for evaluating the effects of UAP1L1 knockdown/overexpression on GC in vitro and in vivo. The results indicated that UAP1L1 played important role in development of GC through regulating cell proliferation, colony formation, cell apoptosis and cell migration. Subsequently, CDK6 was identified as a potential target in UAP1L1 induced regulation of GC, downregulation of which exhibited similar inhibition effects on GC with UAP1L1. Moreover, it was demonstrated that the promotion of GC by UAP1L1 overexpression could be significantly attenuated or even reversed by simultaneously silencing CDK6. In conclusion, UAP1L1 was reported to be a tumor promotor in the development and progression of GC which may exert its role through regulating CDK6 and may act as a candidate of therapeutic target in treatment.

New Energy Setup Strategy for Intact N-Glycopeptides Characterization Using Higher-Energy Collisional Dissociation.

With the optional setting of multiple stepped collisional energies (NCEs), higher-energy collisional dissociation (HCD) as available on Orbitrap instruments is a widely adopted dissociation method for intact N-glycopeptides characterization, where peptide backbones and N-glycan moieties are selectively fragmented at high and low NCEs, respectively. Initially, a dependent setting of a central value plus minus a variation is available to the users to set up NCEs, and the combination of 30 ± 10% to give the energies 20%/30%/40% has been mostly adopted in the literature. With the recent availability of an independent NCEs setup, we found that the combination of 20%/30%/30% is better than 20%/30%/40%; in the analysis of complex intact N-glycopeptides enriched from gastric cancer tissues, total IDs with spectrum-level FDR ≤ 1%, site-specific IDs with site-determining fragment ions, and structure-specific IDs with structure-diagnostic fragment ions were increased by 42% (4,767 → 6,746), 57% (599 → 942), and 97% (1771 → 3495), respectively. This finding will benefit all the coming N-glycoproteomics studies using HCD as the dissociation method.