Stage Gastric Cancer Patients Research Articles

Integrin-β6 Serves as a Potential Prognostic Serum Biomarker for Gastric Cancer.

Discovering novel biomarkers that easily accessed is a key step towards the personalized medicine approach for gastric cancer patients. Integrin-β6 (ITGB6) is a subtype of integrin that is exclusively expressed on the surface of epithelial cells and is up-regulated in various tumors. In the present study, a retrospective cohort with 135 gastric cancer patients and a prospective cohort with 34 gastric cancer patients were constructed, ITGB6 expression were detected in both the serum specimens and the tissue specimens. Detailed clinicopathological parameters as well as patients’ survival were recorded. A nomogram including ITGB6 expression was also constructed and validated to predict the prognosis of gastric cancer patients. Results showed that serum ITGB6 expression was obviously increased and associated with tumor stage in gastric cancer patients, serum ITGB6 expression was relatively high in patients with liver metastasis. High ITGB6 expression indicated a poor prognosis, and nomogram including serum ITGB6 expression could predict the prognosis of gastric cancer patients effectively. Moreover, serum ITGB6 expression was associated with ITGB6 expression in tumor tissues. Furthermore, combined serum ITGB6 and CEA levels contributed to the risk stratification and prognostic prediction for gastric cancer patients. In addition, the serum expression of ITGB6 decreased significantly after radical surgery, and a new rise in serum ITGB6 expression indicated tumor recurrence or progression. The present study identified a novel serum biomarker for the risk stratification, prognostic prediction and surveillance of gastric cancer patients.

NUDT21 Promotes Tumor Growth and Metastasis Through Modulating SGPP2 in Human Gastric Cancer.

Gastric cancer is one of the major malignancies with poor survival outcome. In this study, we reported that NUDT21 promoted cell proliferation, colony formation, cell migration and invasion in gastric cancer cells. The expression levels of NUDT21 were found to be much higher in human gastric cancer tissues compared with normal gastric tissues. NUDT21 expression was positively correlated with tumor size, lymph node metastasis and clinical stage in gastric cancer patients. High level of NUDT21 was associated with poor overall survival (OS) rates in gastric cancer patients. The expression levels of NUDT21 were also much higher in gastric cancer tissues from patients with tumor metastasis compared with those of patients without tumor metastasis. Moreover, forced expression of NUDT21 in gastric cancer cells promoted tumor growth and cell proliferation in xenograft nude mice, and depletion of NUDT21 in gastric cancer cells restrained lung metastasis in vivo. Through high throughput RNA-sequencing, SGPP2 was identified to be positively regulated by NUDT21 and mediated the tumor promoting role of NUDT21 in gastric cancer cells. Therefore, NUDT21 played an oncogenic role in human gastric cancer cells. NUDT21 could be considered as a novel potential target for gastric cancer therapy.

Overexpressed LINC00467 promotes the viability and proliferation yet inhibits apoptosis of gastric cancer cells via raising ITGB3 level

Long non-coding RNA (lncRNA) LINC00467 plays a proto-oncogenic role in non-small cell lung cancer. However, its effect and modulatory mechanism in gastric cancer (GC) are unknown. Thereby, we elucidated the mechanism of LINC00467 in GC. LINC00467 level in GC tissues was assessed by bioinformatic analysis, and clinicopathological parameters from GC patients were collected. The levels of LINC00467, integrin subunit beta 3 (ITGB3), proliferating cell nuclear antigen (PCNA), cleaved caspase-3 and cleaved poly (ADP-ribose) polymerase 1 (PARP1) in tissue samples or treated GC cells were assessed by quantitative real-time polymerase chain reaction (qRT-PCR), fluorescence in situ hybridization (FISH), or Western blot. The viability, proliferation and apoptosis of GC cells were detected by methyl thiazolyl tetrazolium assay, colony formation assay, and flow cytometry. Levels of LINC00467 and ITGB3 were up-regulated in GC, and highly expressed LINC00467 was positively associated with tumor size, differentiation, N stage, and T stage in GC patients. LINC00467 was enriched in cytoplasm of GC cells, and overexpressed LINC00467 promoted the viability and proliferation as well as levels of ITGB3 and PCNA, while suppressing the apoptosis and levels of cleaved caspase-3 and cleaved PARP1 in GC cells. Besides, the effects of shLINC00467 on inhibiting cell viability, proliferation of GC cells and PCNA level and promoting apoptosis as well as levels of cleaved caspase-3 and cleaved PARP1 were all partially reversed by overexpressed ITGB3. Overexpressed LINC00467 enhanced the viability and proliferation but inhibited apoptosis of GC cells via increasing ITGB3 level.

Tumor-derived LIF promotes chemoresistance via activating tumor-associated macrophages in gastric cancers

Chemotherapy is the preferred clinical treatment for advanced stage gastric cancer (GC) patients, of which efficacy could be markedly impaired due to the development of chemoresistance. Alternatively activated or M2-type tumor associated macrophages (TAMs) are recruited under chemotherapy and are highly implicated in the chemoresistance development, but underlying molecular mechanism for TAM activation is largely unknown. Here, we present that tumor-derived Leukemia inhibitory factor (LIF) induced by chemo drugs represses the chemo sensitivity of gastric tumor cells in a TAM-dependent manner. Mechanistically, cisplatin-induced HIF1α signaling activation directly drive the transcription of LIF, which promotes the resistance of gastric tumors to chemo drug. Further study revealed that tumor cell-derived LIF stimulates macrophages into tumor-supporting M2-type phenotype via activating STAT3 signaling pathway. Therapeutically, blocking LIF efficiently elevates chemo sensitivity of tumor cells and further represses the growth rates of tumors under chemotherapy. Therefore, our study reveals a novel insight in understanding the cross talking between tumor cells and immune cells and provides new therapeutic targets for gastric cancer.

Comprehensive Analysis of SFRP Family Members Prognostic Value and Immune Infiltration in Gastric Cancer.

Gastric cancer (GC) is the fifth most common cancer globally. Secreted frizzled-related proteins (SFRP) are important elements associated with the Wnt signaling pathway, and its dysregulated expression is found in multiple cancers. However, the function of distinct SFRPs in GC remains poorly understood. We investigated the differential expression, prognostic value, and immune cell infiltration of SFRPs in gastric cancer patients from the Oncomine, Gene Expression Profiling Interactive Analysis (GEPIA), UALCAN, Kaplan–Meier plotter, cBioPortal, STRING, Gene-MANIA, DAVID, MethSurv, and TIMER databases. We found that the expression levels of SFRP2 and SFRP4 were significantly increased in GC tissues, whereas the SFRP1 and SFRP5 expressions were reduced. SFRP1, SFRP2, and SFRP5 were significantly correlated with the clinical cancer stage in GC patients. Higher expression of SFRPs was associated with short overall survival (OS) in GC patients. Besides, high SFRPs methylation showed favorable OS in GC patients. The functions of SFRPs were primarily related to the Wnt signaling pathway, immune system development, and basal cell carcinoma. The expression of SFRPs was strongly correlated with immune infiltrating cells, including CD4+ T cells and macrophages in GC. Our study indicated that SFRPs could be potential targets of precision therapy and prognostic biomarkers for the survival of GC patients.

A noninvasive gastric cancer Her2 test using surrogate methylation markers.

e16084 Background: There are 10-20% of gastric cancer (GC) with overexpressed Her2. Her2 status remains an essential biomarker for guiding the trastuzumab (Herceptin) therapy, a monoclonal antibody approved for the first-line treatment of late-stage Her2-positive GC. Although IHC, together with FISH, is comprehensively applied to verify Her2 status on tissue samples, an accurate blood test is highly desirable due to the inaccessibility of tissue samples, especially in very late stage GC patients as well as tumor heterogeneity of tissue biopsy. Detecting copy number aberration of Her2 gene in cell-free DNA (cfDNA) gains a lot of interest for its non-invasive approach. However, the limited signal-to-noise ratio poses a great challenge for the accuracy and robustness of the tests (either targeted sequencing or ddPCR). Here, we report a non-invasive test for Her2 status verification based on novel surrogate DNA methylation markers. Methods: Genome-wide DNA methylation sequencing was performed in 30 Her2-negative (IHC 0/1+) and 44 Her2-positive (IHC 3+) tissue samples to identify Her2-overexpression-specific methylation markers. Then we analyzed the performance of these candidate markers using methylation-specific quantitative PCR (qMSP) in plasma samples collected from 102 GC patients before surgical treatment. A Her2-status diagnostic model was built and further validated in a multi-center, prospective cohort (n = 150). The concordance of Her2 status between GC plasma and matching tissue samples (IHC/FISH) was determined. Results: We first discovered 102 statistically significant methylation markers of Her2 status in tissue. Out of these candidate markers, a 3-marker diagnostic model was built and validated on plasma samples, which could discriminate Her2-positive from Her2-negative GC patients with high sensitivity (86.7%) and specificity (96.8%). The overall plasma-tissue concordance of this liquid biopsy test was 95.3%. Furthermore, the Her2-status test was able to classify Her2 2+ status (IHC) into either Her2-negative or Her2-positive status, which was confirmed by conventional FISH test. Conclusions: Overall, the cfDNA-based test is a novel, accurate and noninvasive approach for determining Her2 status in GC patients. The high concordance with IHC/FISH results of this blood test holds great promise as an auxiliary method for guiding Her2-targeted therapy in GC patients. A clinical trial is undergoing to validate this test in the phase-2 clinical trial of a Her2-targeted drug (for GC) in China.

Clinical significance of multi-slice spiral CT, MRI combined with gastric contrast-enhanced ultrasonography in the diagnosis of T staging of gastric cancer.

To explore the application value of multi-slice spiral CT (MSCT), magnetic resonance imaging (MRI) combined with gastric contrast-enhanced ultrasonography in the diagnosis of T staging of gastric cancer. The subjects of study were 109 gastric cancer patients with T stages admitted to our hospital for diagnosis and treatment from December 2016 to December 2018. All the patients were examined with MSCT, MRI and gastric contrast-enhanced ultrasonography before operation to observe corresponding imaging results. T staging of gastric cancer patients was conducted according to the examination results, which was then compared with postoperative pathological staging. It was performed to analyze the accuracy of the three diagnostic methods and combined diagnosis of gastric cancer T staging. The sensitivity of MSCT in the diagnosis of T staging of gastric cancer was 60.00%, 67.74%, 72.22%, 76.47%, the specificity was 95.24%, 88.46%, 86.30%, 94.56% and the diagnostic coincidence rate was 87.16%, 82.57%, 81.65%, 91.74%; the sensitivity of MRI in the diagnosis of T staging of gastric cancer was 68.00%, 70.97%, 77.78%, 76.47%, the specificity was 92.86%, 88.46%, 91.78%, 95.65%, and the diagnostic coincidence rate was 87.16%, 83.49%, 87.16%, 92.66%; the sensitivity of gastric contrast-enhanced ultrasonography in the diagnosis of T staging of gastric cancer was 80.00%, 83.87%, 86.11%, 82.35%, the specificity was 97.62%, 92.31%, 91.78%, 97.83%, and the diagnostic coincidence rate was 93.58%, 89.91%, 89.91%, 95.41%; the sensitivity of combined MSCT, MRI and gastric contrast-enhanced ultrasonography in the diagnosis of T staging of gastric cancer was 88.00%, 93.55%, 97.22%, 94.12%; the specificity was 100%, 97.44%, 95.89%, 98.91%; and the diagnostic coincidence rate was 97.25%, 96.33%, 96.33%, 98.17%, respectively. Statistical analysis revealed that the sensitivity, specificity and diagnostic coincidence rate of combined detection of the three methods were significantly higher than those of single detection (P < 0.05). Combined use of MSCT, MRI and gastric contrast-enhanced ultrasonography can significantly improve the diagnostic sensitivity, specificity and diagnostic coincidence rate of T staging of gastric cancer. It may provide a certain reference value for guiding the selection of clinical therapeutic approaches and evaluation of curative effect.

Đánh giá kết quả hóa trị triệu chứng bước 1 ở bệnh nhân ung thư dạ dày giai đoạn tiến xa bằng phác đồ có epirubicin, oxaliplatin, capecitabin

Purpose:to study clinical and subclinical characteristics in advanced stage gastric cancer patients and to evaluate response rate, overall survival, progression free survival and toxicities on advanced stage gastric cancer patients treated with first line chemotherapy using epirubicin, oxaliplatin, capecitabin Methods: A retrospective case series study with 134 advanced stage gastric cancer patients on first line chemotherapy using epirubicin, oxaliplatin, capecitabin recruited from oncology department, the Hospital of Hue University of Medicine and Pharmacy and Cancer Center at Hue Central Hospital during January 2015 to June 2019. Results: Patient’s mean age was 54,9; men/women was 2,52/1. The most frequent clinical symptom reported was epigastric pain 81,3%. KPS 80-90% presented in almost patient (93.3%). The most common site of cancer was pyloric antrum (61,9%). 58,2% patients had distant metastasis disease which liver was the most frequent site. The overall response rate, partial response rate, complete response rate were 49,2%, 42,5%, 6,7% respectively. The median progression free survival was 8,6 ± 0,15 months and the overall survival was 10,7 ± 1,1 months. The pathologic type and combined salvage surgery status were response correlated factors. Grade 3, 4 toxicities in term of hematology, liver and kidney function were only exhibited in a few cases. Patients were tolerated well with chemotherapy. No deaths related to chemotherapy. Conclusions: This study shows that EOX regimen was safe and effective. As a results, we can apply this for first line pallative chemotherapy on advanced stage gastric cancer which KPS ≥70%.

Helios Expression in Tumor-Infiltrating Lymphocytes Correlates with Overall Survival of Advanced Gastric Cancer Patients.

Immunotherapy is a highly promising approach for the treatment of gastric cancer, the third-leading cause of overall cancer death worldwide. In particular, tumor-infiltrating lymphocytes and peripheral blood mononuclear cells are believed to mediate host immune responses, although this activity may vary depending on the activation status and/ or their microenvironments. Here, we examined the expression of a specific zinc finger transcription factor, Helios (IKZF2), in gastric tumor-infiltrating lymphocytes by immunohistochemistry and the correlation with survival. Segregation of gastric cancer patients into high- vs. low-Helios-expressing tumor-infiltrating lymphocytes showed those with high expression to exhibit longer survival in gastric cancer patients, Helicobacter pylori-infected gastric cancer patients and advanced stage (III–IV) gastric cancer patients. In particular, Helios expression was an independent factor for survival in advanced gastric cancer patients. We performed immunofluorescence staining to detect Helios expression in tumor-infiltrating lymphocytes and peripheral blood mononuclear cells. We found that Helios is expressed more in CD4+ T cells and little in CD8+ T cells in infiltrated lymphocytes in gastric cancer. In summary, we believe that the study of specific characteristics of tumor-infiltrating lymphocytes can delineate the interactions of immune and tumor cells to improve upon immunotherapy strategies.

Abstract 2437: Clinical, biological and translational significance in gastric cancer of reprimo-like gene, an uncharacterized member of the reprimo gene family

Abstract Background: Gastric cancer (GC) is one of the leading causes of cancer death. Elucidating the molecular bases of GC might contribute to develop opportune diagnostic strategies. Reprimo-like (RPRML) is a poorly characterized member of the Reprimo gene family. The founding member of this family, Reprimo, is reported to be a putative tumor suppresser gene and candidate biomarker for GC diagnosis. We have recently reported the downregulation of RPRML expression in GC tissues compared to paired normal adjacent tissues, and that in vitro expression is regulated by DNA methylation. We hypothesize that RPRML promoter methylation may act as a non-invasive biomarker for GC. Methods: RPRML expression was evaluated by immunohistochemistry (IHC) in 91 GC cases from The Gastric Cancer Task Force (NCT03158571). Two pathologists scored staining by multiplying the proportion and the intensity of stained cells (range 0-3). Cox proportional hazard ratio was applied to determine an association between RPRML IHC score and global survival, after adjusting by stage. In addition, we investigated the effect of RPRML overexpression in GC cell behavior in vitro through the stable transfection and sorting of RPRML coupled to GFP or GFP alone in the AGS cell line. Functional assays included Ki67 immunofluorescence, colony formation, soft agar, transwell migration and wound healing assays. All experiments were performed in biological triplicate and Kruskal-Wallis statistical analysis applied. The Methylight assay was used to quantify methylated RPRML DNA copies in plasma samples from 25 GC cases (tumor bank repository BTHCUCH) and 25 healthy donors under an endoscopic surveillance program (PREVECAN). ROC curve analysis was performed to determine the cut-off value for the highest sensitivity and specificity. Results: Among 91 GC cases, RPRML expression showed a median IHC score of 0.024 (range 0-2.45). By using the median as a cut-off point, low RPRML IHC score was associated with poor overall survival of stage III and IV GC patients (HR=2.13, 95%CI:1.1-4.1, p=0.02). In vitro overexpression of RPRML inhibited cell proliferation (p=0.04) and resulted in reduced clonogenic capacity (p=0.001) and anchorage independent growth (p≤0.0001). Furthermore, RPRML overexpression retarded migration and wound healing in AGS cells. Methylation of RPRML DNA in plasma samples discriminated between GC patients and controls with an AUC of 0.66. Utilizing a cut-off value of 0.15 copies/ul, sensitivity was 56% (95%CI: 34.9 - 75.6) and specificity 72% (95%CI: 50.6 - 87.9). Conclusion: RPRML downregulation associated with poor survival of advanced stage GC patients. In accordance, ectopic overexpression of RPRML in vitro inhibited biological characteristics associated with tumor progression, suggesting that RPRML may have a tumor suppressor role in GC. Future analysis will determine if the methylation of RPRML is a candidate marker for the non-invasive detection of GC. Grants: CONICYT-FONDAP 15130011 and Fondecyt 1191928 Citation Format: Maria Alejandra Alarcon, Wilda Olivares, Andres Rodriguez, Maria Jose Maturana, Rocío Bustos, Iva Polakovicova, Miguel Cordova-Delgado, Matías Muñoz-Medel, Marcelo Garrido, Gareth I. Owen, Tomas De Mayo, Gonzalo Carrasco-Avino, Julio Amigo, Arnoldo Riquelme, Robinson Gonzalez, Carlos Barrientos, Edmundo Aravena, Franz Villarroel-Espíndola, Alejandro H. Corvalan. Clinical, biological and translational significance in gastric cancer of reprimo-like gene, an uncharacterized member of the reprimo gene family [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 2437.

High plasma levels of COL10A1 are associated with advanced tumor stage in gastric cancer patients.

BACKGROUNDGastric cancer (GC) remains an aggressive malignancy with a high rate of mortality, being the third leading cause of cancer-related death. More than one million newly diagnosed cases and 782685 deaths due to GC were reported in 2018. GC is characterized by limited effective treatment options and the lack of consistent biomarkers for the diagnosis and prognosis of these patients. The discovery of new biomarkers useful in the early diagnosis of GC is mandatory.AIMTo evaluate the potential of COL10A1 as a circulating biomarker for the diagnosis and prognosis of gastric adenocarcinoma patients.METHODSPlasma and tissue obtained from 49 patients with gastric adenocarcinoma have been used in exploring the expression of COL10A1. Real-time PCR and western blot techniques were used to evaluate COL10A1 level in gastric tumor tissue compared to normal adjacent tissue. The circulating level of COL10A1 was also evaluated by ELISA in plasma of gastric adenocarcinoma patients. Survival analysis was made in order to evaluate the potential of COL10A1 as a biomarker for the diagnosis and prognosis of gastric adenocarcinoma patients.RESULTSOur results showed a significant increase in COL10A1 gene expression and protein levels in gastric tumor tissue compared to adjacent normal tissue (P < 0.05). COL10A1 seems to show an elevated expression from the beginning of carcinogenesis, in the early stages, and its increased level remains elevated during cancer progression. A significant increase of COL10A1 plasma level in gastric adenocarcinoma patients was also identified. Moreover, increased COL10A1 plasma level was associated with poor survival of the patients. Plasma COL10A1 performed a diagnostic value in GC with area under the receiver operating characteristic curve (AUC) of 0.9171 (P = 0.0002), sensitivity of 87.76%, and specificity of 100.0%. Furthermore, this study demonstrated the potential role of plasma COL10A1 in the early detection of GC, as in the early stage, we obtained an AUC of 0.8789 (P = 0.0030), sensitivity of 81.25%, and specificity of 100.0%.CONCLUSIONCirculating expression level of COL10A1 is significantly increased in gastric adenocarcinoma patients being associated with poor survival and is a potential biomarker for early detection of GC.

Activated HIF1α of tumor cells promotes chemoresistance development via recruiting GDF15-producing tumor-associated macrophages in gastric cancer.

Chemotherapy is the preferred treatment for advanced stage gastric cancer (GC) patients, and developing chemoresistance is a tremendous challenge to efficacy of GC treatment. The treatments of anti-tumor chemo-agents recruit more tumor-associated macrophages (TAMs) which are highly implicated in the chemoresistance development, but the underlying molecular mechanism is unclear. Here, we demonstrate that hypoxia-inducible factor 1α (HIF1α) in GC cells is activated upon 5-fluorouracil (5-FU) treatment and results in much more accumulation of M2-type TAMs which protect tumor cells from chemo-agents. Mechanistically, in the GC cells under the 5-FU treatment, reactive oxygen species is accumulated and then induces the activation of HIF1α signaling to drive the expression of high-mobility group box 1, which leads to more macrophage's infiltration into GC tumor. In turn, the recruited TAMs exhibit tumor-protected M2-type phenotype and promote the chemoresistance of GC cells via producing growth differentiation factor 15 (GDF15) to exacerbate the fatty acid β-oxidation in tumor cells. Blocking GDF15 using antibody or inhibiting FAO of tumor cells by etomoxir efficiently gave rise to the tumor cell sensitivity to 5-FU. Therefore, our study demonstrates a novel insight in understanding the cross talking between tumor cells and immune microenvironment and provides new therapeutic targets for clinic treatments of gastric cancer.

Circ_0001023 Promotes Proliferation and Metastasis of Gastric Cancer Cells Through miR-409-3p/PHF10 Axis.

BackgroundCircular RNAs (circRNAs) have been well documented to regulate the gene expression via sponging microRNA (miRNA) in diverse neoplasms including gastric cancer (GC).MethodsIn the present study, the expressions of circ_0001023, miR-409-3p, and plant homeodomain finger 10 (PHF10) in GC tissues were detected by qRT-PCR. Chi-square test was performed to analyze the associations between circ_0001023 and pathological parameters. Cell Counting Kit-8 assay, colony formation assay, flow cytometry, and transwell assay were adopted to detect the role of circ_0001023/miR-409-3p axis in the proliferation, apoptosis, and migration of GC cells, respectively. The targeting relationship between circ_0001023 and miR-409-3p was investigated by dual-luciferase gene reporter gene assay. Additionally, subcutaneous xenotransplanted tumor model in nude mice was established to detect the function of circ_0001023 on GC growth in vivo.ResultsCompared with adjacent tissues, the expression of circ_0001023 was significantly upregulated and correlated with lymph node invasion and higher T stage of GC patients. It has also been proved that circ_0001023 could target miR-409-3p. Silencing circ_0001023 can impede the proliferation of GC cells and promote apoptosis, while miR-409-3p inhibitors can partially reverse the biological behavior of GC cells mentioned above. Moreover, the expression of circ_0001023 was reversely associated with miR-409-3p expression but positively correlated with PHF10, a downstream oncogene of miR-409-3p.ConclusionCollectively, it is concluded that circ_0001023 promotes the progression of GC via regulating miR-409-3p/PHF10 axis.

Exploration of potential beneficial people of neoadjuvant chemotherapy based on clinical staging in gastric cancer: a single center retrospective study

Objective: To evaluate the accuracy of the clinical staging by comparing preoperative clinical stage and pathological stage in gastric cancer patients, and to explore the potential beneficial population of neoadjuvant chemotherapy for gastric cancer. Methods: We retrospectively collected the clinical data of consecutive patients with gastric cancer who met the inclusion criteria (gastric adenocarcinoma, undergoing laparoscopic or open D2 radical operation, definite cTNM and pTNM) for admission of the Gastrointestinal Center of Peking University Cancer Hospital from July 2013 to April 2019. Patients with the number of harvested lymph nodes less than 16, history of gastric operation or preoperative radiochemotherapy were excluded. Preoperative clinical stage was obtained from abdominal and pelvic enhanced CT by radiologists, and postoperative pathological stage was derived from postoperative pathology reports. The concordance rate between preoperative clinical stage and postoperative pathological stage, and the proportion of pathological stage I in patients with specific preoperative clinical TNM stage were analyzed and compared. The potential beneficial population of neoadjuvant chemotherapy were considered as pI < 5%. Relationship between clinical features and concordance rate of stage was further analysed. Results: A total of 459 patients were included in the analysis, including 321 males and 138 females with mean age of 60 (23 to 85) years old. The concordance rate from T1 to T4 between preoperative clinical T staging and postoperative pathological T staging was 82.5% (33/40), 31.1% (28/90), 34.4% (62/180), and 55.0% (96/149), respectively. The concordance rate from N0 to N3 between preoperative clinical N staging and postoperative pathological N staging was 58.8% (134/228), 22.1% (19/86), 23.6% (26/110), and 54.3% (19/35), respectively. The sensitivity and specificity of abdominal enhanced CT in the diagnosis of lymph node metastasis were 64.5% (171/265) and 69.1% (134/194) respectively. The clinical stage of cT3/T4 patients with pathological stage I was 9.1% (30/329), and the sensitivity of corresponding pathological stage III was 94.8% (164/173), while the cT3/4+cN1-3 patients with pathological stage I stage was 1.4% (3/218), and the sensitivity of corresponding pathological phase III was 76.9% (133/173). Tumor location was associated with the concordance of cT/pT staging [gastroesophageal junction: 64 (56.6%), upper stomach: 9 (9/17), middle stomach: 31 (40.3%), lower stomach: 97 (39.9%), whole stomach: 4(4/9), χ(2)=9.845, P=0.043]; the degree of tumor differentiation was associated with the concordance of cN/pN staging [poorly differentiated: 94 (42.3%), moderated differentiated: 92 (41.1%), well differentiated: 12 (12/13), χ(2)=13.261, P=0.001], whose differences were statistically significant (all P<0.05). Conclusion: Based on a single-center retrospective data from Peking University Cancer Hospital, we think that the potential beneficial population of neoadjuvant chemotherapy for gastric cancer are those clinically staged as cT3/4+N1-3.

Negative lymph node count as an independent prognostic factor in stage III patients after curative gastrectomy: A retrospective cohort study based on a multicenter database.

To examine the prognostic value of negative lymph node (NLN) count in stage III gastric cancer (GC) patients after curative gastrectomy. The clinicopathological data of 2942 stage III patients who underwent curative gastrectomy between 2001 and 2011 were analyzed. Only patients with ≥16 examined lymph nodes (ELNs) were included. After cut-point survival analysis, the 2942 patients were divided into three subgroups with NLN counts of 0, 1-9, and ≥10. Survival differences among the subgroups were analyzed to assess the effects of NLN count on stage migration and overall survival (OS) in stage III GC patients. Spearman's correlation coefficient was used to assess the relationships between the ELN count and the positive lymph node (PLN) count, the ELN count and the NLN count, and the NLN count and the PLN count. Survival analyses revealed that the NLN count was significantly associated with OS (P=0.001) and was an independent predictor (P<0.01) of prognosis in stage III GC patients. Subgroup analysis showed that the prognostic evaluation accuracy was highest when the NLN count was ≥10 for stage III patients. Stage migrations were mainly detected in the following pathological tumor-node (pTN) subgroups: pT2N3a with 1-9 NLNs and pT2N3b with ≥10 NLNs, and pT3N3a with 1-9 NLNs and pT3N3b with ≥10 NLNs. NLN count was positively correlated with the ELN and the PLN counts for pT2N3 and pT3N3 stage GC patients (r=0.694 and r=0.881 for pT2N3 patients; r=0.685 and r=0.902 for pT3N3 patients, respectively; P<0.001). These findings indicate that the NLN count may be a useful prognostic predictor in stage III GC patients. The NLN count may improve the prognostic prediction efficiency of the tumor-node-metastasis (TNM) classification for GC, especially for stage III patients, and should be recommended for clinical applications.

Late stage gastric cancer patients with extra gained HER2 positivity by dual block assessment may not show compromised efficacy to trastuzumab treatment.

Dual block HER2 assessment can effectively increase the HER2 positive rate in resected specimens of gastric cancer (GC). The aim of this study is to explore whether GC patients with extra gained HER2 positivity by dual block assessment can benefit from trastuzumab therapy. Twenty-eight GC patients receiving gastrectomy prior to trastuzumab treatment were retrospectively analyzed. All the cases routinely accepted dual block HER2 assessment. The cases were divided into 2 cohorts based on HER2 status: cohort A with concordant HER2 results and cohort B with discordant HER2 results between the two blocks (cases with extra gained HER2 positivity). Response rate (RR), progress free survival (PFS) and overall survival (OS) were compared between the two cohorts. The results showed that no significant differences were found between the two cohorts in main clinicopathologic characteristics. No statistical difference was found in response rate (47.6% vs 57.1%) (P=1.0), either. The two cohorts did not demonstrate statistical differences in the PFS (10.5 months (95%CI 6.4-14.6) vs 8.0 months (95%CI 3.2-12.8), P=0.686) and the OS (23.3 months (95%CI 12.1-34.5) vs 20.0 months (95%CI 10.1-29.9), P=0.776). In conclusion, our study suggests that patients with extra gained HER2 positivity may not show compromised efficacy to trastuzumab treatment.

CircLMTK2 acts as a sponge of miR-150-5p and promotes proliferation and metastasis in gastric cancer

BackgroundAs a novel class of non-coding RNAs, circular RNAs (circRNAs) are key regulators of the development and progression of different cancers. However, little is known about the function and biological mechanism of circLMTK2, also named hsa_circ_0001725, in gastric cancer (GC) tumourigenesis.MethodscircLMTK2 was identified in ten paired cancer specimens and adjacent normal tissues by RNA sequencing and genome-wide bioinformatic analysis and verified by quantitative real-time PCR (qRT-PCR). Knockdown or exogenous expression of circLMTK2 combined with in vitro and in vivo assays were performed to prove the functional significance of circLMTK2. The molecular mechanism of circLMTK2 was demonstrated by searching the CircNet database and confirmed by RNA in vivo precipitation assays, western blotting, luciferase assays and rescue experiments.ResultscircLMTK2 was frequently upregulated in GC tissues, and high circLMTK2 expression was associated with poor prognosis, lymph node metastasis and poor TNM stage in GC patients. Functionally, circLMTK2 overexpression promoted GC cell proliferation and tumourigenicity in vitro and in vivo. Furthermore, ectopic circLMTK2 expression enhanced GC cell migration and invasion in vitro and tumour metastasis in vivo. In addition, we demonstrated that circLMTK2 could sponge miR-150-5p, thus indirectly regulating the c-Myc expression and contributing to GC tumourigenesis.ConclusionOur findings demonstrate that circLMTK2 functions as a tumour promoter in GC through the miR-150-5p/c-Myc axis and could thus be a prognostic predictor and therapeutic target for GC.

LncRNA PTCSC3 Is a Biomarker for the Treatment and Prognosis of Gastric Cancer.

Background: Long noncoding RNA (lncRNA) papillary thyroid carcinoma susceptibility candidate 3 (PTCSC3) inhibits several types of cancer, whereas its role in gastric cancer is unknown. Materials and Methods: From May 2010 to May 2015, this study included 68 (36 males and 32 females, 35-69 years, 48.3 ± 7.1 years) gastric cancer patients and 60 healthy volunteers (32 males and 28 females, 34-67 years, 48.8 ± 6.5 years). Transient transfections, QPCR, CCK-8, transwell cell migration, and invasion assay were used for carrying out the research. Results: The authors found that plasma PTCSC3 was downregulated in gastric cancer patients. Downregulation of PTCSC3 distinguished early stage gastric cancer patients from healthy controls. LncRNA PTCSC3 expression levels were increased on the day of discharge in gastric cancer patients compared with pretreatment levels. During follow-up, patients with low plasma levels of PTCSC3 showed a significantly lower overall survival rate. PTCSC3 negatively regulated proliferation, invasion, and migration of gastric cancer cells. Conclusions: Therefore, lncRNA PTCSC3 may serve as a biomarker for the treatment and prognosis of gastric cancer.

134P - Identification, development and validation of a circulating miRNA-based diagnostic signature for early detection of gastric cancer

BackgroundAlthough endoscopic surveillance remains the gold standard for diagnosing asymptomatic gastric cancer (GC) patients, associated costs and its invasive nature render it inadequate as a screening approach. Development of less invasive tests is needed for surveillance of early stage GCs. Over the last decade, tumor-derived miRNAs in peripheral blood are emerging as promising disease biomarkers. Herein we have conducted a comprehensive miRNA expression profiling, followed by bioinformatic analysis to establish a novel serum-based miRNA signature for the diagnosis of patients with GC. MethodsWe analyzed tissue miRNA expression profiles in three patient cohorts (n = 602) in an in-silico discovery step, during which the robustness of candidate biomarkers was tested and validated. The performance of this miRNA signature was evaluated in a serum training cohort (n = 327). Using a logistic regression model, the panel was further refined, and this circulating miRNA signature was validated in two prospective cohorts (n = 174, 175). ResultsGenome-wide analysis of miRNA expression data resulted in identification of 10-miRNAs that distinguished cancer tissues from normal mucosa in three independent datasets (AUC = 0.984, 0.939 and 1.000). Using a serum training cohort, the miRNA candidates were further refined to six-circulating-miRNA signature. This miRNA signature demonstrated a robust diagnostic value in the training cohort. Subsequently we demonstrated robustness of the signature in two prospective cohorts (AUC = 0.87, 0.86). Remarkably, the 6-circulating-miRNA signature was able to detect early stage GC patients robustly (AUC = 0.855). Furthermore, the signature was significantly superior at identifying patients with GC to conventional tumor markers, CEA (P = 0.0001) and CA19-9 (P = 0.0001). ConclusionsUsing a comprehensive data analysis followed by substantial clinical validations, involving over 1600 GC tissue and serum specimens across 7 independent cohorts, we developed a novel 6-circulating-miRNA signature, which demonstrated an unprecedented diagnostic value and a great promise for early non-invasive detection of GC. Legal entity responsible for the studyDaisuke Izumi. FundingNIH. DisclosureAll authors have declared no conflicts of interest.

PDRG1 gene silencing contributes to inhibit the growth and induce apoptosis of gastric cancer cells

ObjectiveThis paper aims to provide some experimental basis for unveiling the role of PDRG1 (P53 And DNA Damage-Regulated Gene 1) gene silencing in the growth and development of gastric cancer. MethodsPDRG1 levels in gastric cancer tissues and cell lines were measured by Western blotting. Then, gastric cancer BGC-823 cells, divided into Control, PDRG1 siRNA, NC siRNA and PDRG1 siRNA + KU55933 (ATM inhibitor) groups, were used to conduct a series of in vitro experiments including MTT, Flow cytometry, Wound-healing and Transwell assays. Expression of PDRG1 and ATM/p53 pathway-related proteins were determined by Western blot. Eventually, experiment in vivo was carried out to verify the control of PDRG1 on gastric cancer cells after establishing the tumor xenograft model in nude mice. ResultsPDRG1 was significantly elevated in gastric cancer tissues and was associated with lower cell differentiation degree, more severe lymph node metastasis and higher tumor stage of gastric cancer patients. The growth of BGC-823 cells were significantly retarded and the cell apoptosis was increased in the PDRG1 siRNA group; besides, cell cycle was arrested in G2/M phase, and the expressions of p-ATM, p53, p21, p-cdc2 and cleaved caspase-3 were up-regulated with the reduced PDRG1. However, KU55933 could reverse the anti-tumor effect of PDRG1 siRNA on BGC-823 cells. The in-vivo experiment confirmed PDRG1 siRNA can inhibit tumor xenograft growth in nude mice. ConclusionSpecific PDRG1 gene silencing may inhibit the growth and metastasis of gastric cancer cells through the activation of ATM/p53 pathway.