Undifferentiated Gastric Cancer Research Articles

Gender Differences in Patients with Gastric Adenocarcinoma.

Background: Gastric cancer (GC) epidemiology and outcomes vary by gender. Methods: We reviewed 18,436 GC patients from 2008 to 2018 and looked for gender differences in clinical characteristics and survival. Results: The gender proportion was 71% male and 29% female. Males had a significantly (p < 0.001) higher proportion of differentiated GC (66.3%) and a lower proportion of undifferentiated GC (26.3%). Diagnosis through medical check-ups was more common in males (30.0% vs. 26.4%, p < 0.001). Clinical staging revealed 54.6% of males and 52.9% of females had localized disease without lymph node metastasis (LNM), while distant metastasis occurred in 17.4% of males and 16.9% of females (p < 0.001). Kaplan-Meier survival curves indicated females had a significantly higher overall survival (p = 0.0018). The survival advantage for females was evident in the early stages, with a significant difference in localized disease without LNM (p < 0.001) and localized disease with LNM (p = 0.0026, log-rank test) but not in the advanced stages. Multivariate Cox regression analysis showed a significantly reduced mortality risk in females (p < 0.001). Conclusions: Significant gender differences exist with regard to pathological type, presentation, clinical stage, and overall survival. These findings suggest gender-specific strategies for screening, diagnosis, and treatment.

Clinical and Genetic Characteristics of Early and Advanced Gastric Cancer.

Gastric cancer (GC) persists as the fourth most prevalent cause of global cancer-related mortality, presenting a challenge due to the scarcity of available therapeutic strategies. Precision medicine is crucial not only in the treatment but also in the management of GC. We performed gene panel sequencing with Oncomine focus assay comprising 52 cancer-associated genes and MSI analysis in 100 case-matched gastric cancer cases. A comprehensive analysis of clinical and genetic characteristics was conducted on these genetic results and clinicopathological findings. Upon comparison of clinicopathological characteristics, significant differences between early gastric cancer (EGC) and advanced gastric cancer (AGC) were observed in tumor location (p = 0.003), Lauren classification (p = 0.015), T stage (p = 0.000), and N stage (p = 0.015). The six most frequently mutated genes were PIK3CA (29%, 10/35), ERBB2 (17%, 6/35), KRAS (14%, 5/35), ALK (6%, 2/35), ESR1 (6%, 2/35), and FGFR3 (6%, 2/35). Regarding genetic variation, there was a tendency for the N stage to be higher in GC patients with mutated genes (p = 0.014). The frequency of mutations in GC patients was statistically significantly higher in AGC (n = 24) compared to EGC (n = 11) (odds ratio, 2.792; 95% confidence interval, 1.113 to 7.007; p = 0.026). Six of the ten GC patients carrying mutated genes and exhibiting MSI were classified into intestinal-type and undifferentiated GC, with the location of the tumor being in the lower-third. Among these patients, five harbored mutated PIK3CA, while the remaining patient had a mutation in ALK. Conclusions: AGC patients more frequently exhibited alterations of PIK3CA, KRAS, and ERBB2 as somatic oncogenic drivers, and displayed a higher prevalence of cumulative genetic events, including increased rates of PIK3CA mutations, enhanced detection of immunotherapy biomarkers, and mutations of the ESR1 gene.

Dual PI3K/mTOR inhibitor PF-04979064 regulates tumor growth in gastric cancer and enhances drug sensitivity of gastric cancer cells to 5-FU

Gastric cancer (GC) is characterized by high tumor heterogeneity, increased surgical difficulty, and limited chemotherapy efficacy, and it is associated with a poor prognosis. The abnormal proliferation of cells involves abnormal activation of the PI3K/AKT/mTOR signaling pathway. Inhibition of this signaling pathway can inhibit tumor cell proliferation and induce cell apoptosis. This study evaluated the effect of PF-04979064, a dual inhibitor of PI3K and mTOR, on human GC cells. PF-04979064 significantly inhibited the proliferation of human gastric adenocarcinoma AGS cells and the undifferentiated GC cell line HGC-27, promoting cell apoptosis. Combination treatment with PF-04979064 and the GC first-line clinical drug 5-FU showed synergistic effects, and PF-04979064 markedly increased the sensitivity of GC cells to chemotherapy drugs. Western blot results showed that PF-04979064 significantly inhibited the PI3K/AKT/mTOR signaling pathway in GC cells, whereas RNA seq results demonstrated substantial alterations in gene expression profiles upon treatment with PF-04979064. This study provides insight into the effects of PF-04979064, thereby establishing a solid foundation for its potential clinical application in the treatment of GC.

Feasibility study fulfilling expanded endoscopic resection criteria in mucosal undifferentiated gastric cancer.

The indication of endoscopic submucosal dissection (ESD) for mucosal undifferentiated early gastric cancer (EGC) remains controversial because of risk of lymph node metastasis (LNM). The aim of this study was to identify risk factors for lymph node metastasis (LNM) in mucosal undifferentiated EGC, and further to confirm feasibility of the ESD for the treatment of mucosal undifferentiated EGC. We retrospectively reviewed data of patients who underwent surgical resection with lymph node dissection of T1a stage primary gastric adenocarcinoma at three medical centers between 2012 and 2022. We evaluated the frequency of lymph node metastasis and the associated risk factors, as well as the lymph node metastasis rate in the expanded indication of mucosal undifferentiated EGC. A total of 100 surgically treated patients with mucosal undifferentiated EGC were enrolled. LNM was irrelevant to the age, tumor size, location, and macroscopic type (all P>0.05), while it was significantly associated with lymphovascular invasion (LVI, P ＜0.001). And logistic regression analysis showed that the LVI was the only significant risk factors for LNM (OR: 0.34, 95%CI: 0.06-0.204; P ＜0.001). Of 44 mucosal undifferentiated EGC patients satisfying the expanded indication of ESD, 3 patients (6.8%) showed LN metastasis, all of them with undifferentiated cancer without ulceration, less than 2.0cm in size. Because LNM is present in mucosal undifferentiated EGC patients who satisfied the expanded indication of ESD, ESD cannot be considered a better choice than surgery for all undifferentiated EGC patients. LVI was significant risk factors for LNM in patients with mucosal undifferentiated EGC.

Development of o-aminobenzamide salt derivatives for improving water solubility and anti-undifferentiated gastric cancer.

Background: Gastric cancer is one of the cancers with wide incidence, difficult treatment and high mortality in the world, especially in Asia and Africa. In our previous work, a novel o-aminobenzamide analogue F8 was identified as an early preclinical candidate for treatment of undifferentiated gastric cancer (IC50 of 0.26μM for HGC-27). However, the poor water solubility of compound F8 prevents its further progress in preclinical studies. Aim: To improve the water solubility and drug-likeness of F8 via salt formation. Method: Different acids and F8 were reacted to obtain different salt forms. Physicochemical property screening, pharmacokinetic property research, and antitumor biological activity evaluation in vitro and in vivo were used to obtain the optimal salt form with the best druggability. Results: our continuous efforts have finally confirmed F8·2HCl as the optimal salt form with maintained in vitro antitumor activity, improved water solubility and pharmacokinetic properties. Importantly, the F8·2HCl displayed superior in vivo antitumor efficacy (TGI of 70.1% in 75mg/kg) in HGC-27 xenograft model. The further immunohistochemical analysis revealed that F8·2HCl exerts an antitumor effect through the regulation of cell cycle-related protein (CDK2 and p21), apoptosis-related protein Cleaved Caspase-3, proliferation marker Ki67, and cell adhesion molecule E-cadherin. In addition, F8·2HCl showed acceptable safety in the in vivo acute toxicity assay. Conclusion: Salting is an effective means to improve the drug-like properties of compound F8, and F8·2HCl can serve as a promising therapeutic agent against undifferentiated gastric cancer.

Differences in clinical features and morphology between differentiated and undifferentiated gastric cancer after Helicobacter pylori eradication.

Although undifferentiated gastric cancer (UGC) diagnosed after Helicobacter pylori eradication (HPE) carries a poor prognosis, characteristics of post-HPE UGC have not been evaluated in detail because of its low incidence. Therefore, we compared the clinicopathologic characteristics of UGC and differentiated gastric cancers (DGC) diagnosed after successful HPE. GC lesions from patients who had successfully completed HPE and who had undergone upper gastrointestinal endoscopy between January 2004 and March 2016 were analyzed. Tumors were divided into DGC and UGC groups. Clinicopathologic factors of background and tumor characteristics were compared using univariate and multiple logistic analyses. A total of 129 tumors from 115 patients were evaluated; 113 tumors were in the DGC group and 16 in the UGC group. Depressed-type tumors (P = 0.024) and sub-submucosal invasion (P<0.001) were significantly higher in the UGC group. The UGC group had larger tumor diameters (25.9±7.3 mm) than the DGC group (13.2±10.2 mm) (P<0.001). Multivariate analysis showed that female sex (odds ratio [OR] 3.24, 95%CI:1.02-10.37; P = 0.047) and absent follow-up (OR 4.99, 95%CI:1.60-15.57; P = 0.006) were significant independent risk factors for UGC. The DGC group showed a gradually decreasing temporal trend by trend test (P = 0.015), while the UGC group showed a relatively constant incidence over time, although the number of cases was small. UGC was diagnosed even after long time spans following HPE, although the number of cases was small. Female sex, and especially absent follow-up, were risks for post-HPE UGC, suggesting that diligent long-term follow-up after HPE is essential.

Effects of Astragalin on apoptosis of undifferentiated gastric cancer cells

To investigate the effects and related molecular mechanisms of Astragalin on undifferentiated gastric cancer cell HGC-27. Astragalin was used to treat HGC-27 cells, the cell proliferation activity was detected by CCK-8 method, the cell morphology was observed under inverted microscope, hoechst 33342 and JC-1 staining were used to observe the changes of nucleus formation and mitochondrial membrane potential, the cell cycle and apoptosis rate were detected by flow cytometry, the reverse transcription level of the gene was analyzed by the second-generation sequencer. Astragalin inhibited the proliferation of HGC-27 significantly (P＜0.01), down-regulated mitochondrial membrane potential, induced cell apoptosis, blocked the cell cycle in G1 prophase. At the same time, Astragalin up-regulated the transcription levels of genes bax and bad, down-regulated the transcription levels of genes egf, egfr, pik3cb, pdk1, akt3 and bcl-2. Western blot analysis also showed that the expressions of PI3K and Akt protein were decreased, and the proportion of Bax and BCL-2 protein was increased significantly (P＜0.01). The apoptosis of undifferentiated gastric cancer cell line HGC-27 can be induced by Astragalin through inhibition of EGFR/PDK/Akt signaling pathway, and the cell cycle can be blocked in G1 phase, which has a certain therapeutic effect on undifferentiated gastric cancer.

Autonomous and intercellular chemokine signaling elicited from mesenchymal stem cells regulates migration of undifferentiated gastric cancer cells.

Accumulating evidence demonstrates that bone marrow (BM)-derived mesenchymal stem cells (MSCs) play critical roles in regulating progression of various types of cancer. We have previously shown that Wnt5a-Ror2 signaling in MSCs induces expression of CXCL16, and that CXCL16 secreted from MSCs then binds to its cognate receptor CXCR6 on the surface of an undifferentiated gastric cancer cell line MKN45 cells, eventually leading to proliferation and migration of MKN45 cells. However, it remains unclear about a possible involvement of another (other) cytokine(s) in regulating progression of gastric cancer. Here, we show that CXCL16-CXCR6 signaling is also activated in MSCs through cell-autonomous machinery, leading to upregulated expression of CCL5. We further show that CCR1 and CCR3, receptors of CCL5, are expressed on the surface of MKN45 cells, and that CCL5 secreted from MSCs promotes migration of MKN45 cells presumably via its binding to CCR1/CCR3. These data indicate that cell-autonomous CXCL16-CXCR6 signaling activated in MSCs upregulates expression of CCL5, and that subsequent activation of CCL5-CCR1/3 signaling in MKN45 cells through intercellular machinery can promote migration of MKN45 cells. Collectively, these findings postulate the presence of orchestrated chemokine signaling emanated from MSCs to regulate progression of undifferentiated gastric cancer cells.

Physalin B inhibits cell proliferation and induces apoptosis in undifferentiated human gastric cancer HGC-27 cells.

Physalin B (PB) from Physalis angulata L. (Solanaceae) is a naturally occurring secosteroid with multiple biological activities, including anti-inflammatory and anticancer activity. However, PB's effects and mechanisms in human gastric cancer (GC) cells are not well characterized. The undifferentiated GC cell line HGC-27 and semi-differentiated GC cell line SGC-7901 were treated with PB. Cell counting kit-8 (CCK-8) and colony formation assays were performed to evaluate cell viability. Apoptosis and the cell cycle were assessed by Annexin V/PI and PI/RNase DNA staining assays, respectively, and Western blotting was used to evaluate the expression of a protein. PB significantly inhibited the proliferation of HGC-27 cells in a dose- and time-dependent manner. Moreover, PB induced G0/G1 cycle arrest and caspase-dependent apoptosis of HGC-27 cells. Cleaved caspases 8, 3, and 7, poly(ADP)-ribose polymerase (PARP), and the cyclin-dependent kinase (CDK) inhibitor p-Chk2 was induced by PB in HGC-27 cells, while the cell cycle-related proteins cyclin D1, cyclin D3, CDK4, CDK6, cyclin E, and phosphorylated retinoblastoma tumor suppressor protein (p-Rb) were downregulated in a dose-dependent manner. PB inhibits proliferation via cyclin-dependent kinase and induces caspase-dependent apoptosis in HGC-27 cells, suggesting that PB might be a novel and effective agent for undifferentiated GC therapy.

Immunohistochemical differences in gastric mucosal damage between nodular and non-nodular gastritis caused by Helicobacter pylori infection.

In this study, the level of cell damage were analyzed immuno­histochemically to clarify the association between nodular gastritis and undifferentiated gastric cancer. Thirty patients of nodular gastritis were enrolled as the nodular gastritis group. Thirty patients of non-nodular gastritis were enrolled as the control group. They were evaluated according to the updated Sydney system and used for immunohistochemical staining (p53, Ki-67, E-cadherin, and 8-OHdG). The scores based on the updated Sydney system were significantly higher in the nodular group than in the non-nodular group for histologically assessed inflammation and activity in the gastric corpus (1.91 ± 0.77 vs 1.58 ± 0.60, p = 0.049, 0.83 ± 0.81 vs 0.44 ± 0.64, p = 0.032). On immunostaining, the detection of E-cadherin was lower in the nodular group for both the antrum (1.0 ± 0.62 vs 1.47 ± 0.85, p = 0.047) and the corpus (1.16 ± 0.81 vs 1.48 ± 0.71, p = 0.043) and the p53 labeling index of the gastric corpus was higher in the nodular group than in the non-nodular group (3.06 ± 1.94 vs 2.03 ± 1.99, p = 0.015). Nodular gastritis showed significant severe inflammation and immunohistochemical cell damage compared with non-nodular gastritis. These findings may play an important role in the oncogenesis of undifferentiated gastric cancer in nodular gastritis.

Impact of the Interval between Previous Endoscopic Exam and Diagnosis on the Mortality and Treatment Modality of Undifferentiated-Type Gastric Cancer.

PurposeThe impact of the interval between previous endoscopy and diagnosis on the treatment modality or mortality of undifferentiated (UD)-type gastric cancer is unclear. This study aimed to investigate the effect of endoscopic screening interval on the stage, cancer-related mortality, and treatment methods of UD-type gastric cancer.Materials and MethodsWe reviewed the medical records of newly diagnosed patients with UD gastric cancer in 2013, in whom the interval between previous endoscopy and diagnosis could be determined. The patients were classified into different groups according to the period from the previous endoscopy to diagnosis (<12 months, 12–23 months, 24–35 months, ≥36 months, and no history of endoscopy), and the outcomes were compared between the groups. In addition, patients who underwent endoscopic and surgical treatment were reclassified based on the final treatment results.ResultsThe number of enrolled patients was 440, with males representing 64.1% of the study population; 11.8% of the participants reported that they had undergone endoscopy for the first time in their cancer diagnosis. The percentage of stage I cancer at diagnosis significantly decreased as the interval from the previous endoscopy to diagnosis increased (65.4%, 63.2%, 64.2%, 45.9%, and 35.2% for intervals of <12 months, 12–23 months, 24–35 months, ≥36 months, and no previous endoscopy, respectively, P<0.01). Cancer-related mortality was significantly lower for a 3-year interval of endoscopy (P<0.001).ConclusionsA 3-year interval of endoscopic screening reduces gastric-cancer-related mortality, particularly in cases of UD histology.

774 ENDOSCOPIC SURVEILLANCE INTERVAL MORE THAN 12 MONTHS IS A RISK OF GASTRIC CANCER WITH NON-CURATIVE ENDOSCOPIC RESECTION

Surveillance endoscopy must be performed for patients with a high risk of developing gastric cancer (GC). According to the 5th edition of the Japanese gastric cancer treatment guidelines (JGC-GL), they recommend performing surveillance endoscopy annually or twice a year for high risk patients. The aims of this study were to evaluate the usefulness of surveillance endoscopy for the detection of early-stage gastric cancer and to verify the surveillance intervals of annual or twice a year. We retrospectively analyzed the data of 177 gastric cancer patients who previously underwent surveillance endoscopy at least two times at our hospital from January 2014 to December 2018. The average age of patient were 73.2 (26—93) years. The number of male and female was 131 and 46, respectively. The rate of severe atrophy was 88.0% (147/167). There were 5 uninfected, 34 current, and 132 past infection of Helicobacter pylori, respectively. There were 102 patients with a history of endoscopic resection (ER). The median size of GCs was 9.5 mm. There were 164 differentiated and 13 undifferentiated GCs, 161 mucosal, 14 submucosal, and 2 muscularis propria, respectively. 174 and 3 GCs were resected by ER and surgical resection, respectively. Among the ER cases, 160 were curative ER and 14 were non-curative ER cases due to submucosal invasion, lymph-vascular invasion, or positive margin. Among non-curative ER cases, 8 underwent additional surgical resection, and lymph node metastasis was found in 1 case (12.5%). The median endoscopic surveillance interval from the last endoscopy to the detection of gastric cancer in the curative ER cases was 12 months (5—177). The median interval in the non-curative ER cases and surgical resection cases with non-indication of ER was 14 months (10—63). The rate of patients who had endoscopic surveillance interval more than 12 months were significantly higher in the non-curative ER cases and surgical cases than those in curative ER cases (p=0.0029). Endoscopic surveillance interval more than 12 months identified as a risk factor in multivariate analysis (p=0.0174). Surveillance endoscopy should be performed within12 months to detect gastric cancer with curative ER. A multi-institutional prospective study is necessary to investigate the appropriate interval of surveillance endoscopy.

Clinical Impact of Clinicopathological Characteristics of Undifferentiated Advanced Gastric Cancer in Elderly Patients

Background: Little is known about the clinicopathological findings in elderly patients with undifferentiated advanced gastric cancer. The aim of this study was to clarify the clinical impact of clinicopathological characteristics of those cancers in elderly patients. Method: A total of 42 patients aged 80 years or older with advanced gastric cancer who had undergone curative gastrectomy between 1998 and 2015 were included in this study. All patients were classified into two principal subgroups based on histology: undifferentiated group and differentiated group. The two groups were examined and compared with respect to the pathological findings and clinical outcomes. Results: Of the 47 patients, 23 (49%) patients were in the undifferentiated group and 24 (51%) were in the differentiated group. The undifferentiated cancer was less frequently located in the upper third of the stomach than the differentiated cancer (4% vs 42%, P &lt; 0.01). The frequency of the cancer with depth of T4a was higher in the undifferentiated group than in the differentiated group (48% vs. 17%, P &lt; 0.05). The median number of metastatic lymph nodes in the undifferentiated group was more than that in the differentiated group (3 vs. 1, P &lt; 0.05). In short- and long-term outcome after curative gastrectomy, there were no differences between the two groups. Conclusion: In elderly patients, undifferentiated advanced gastric cancer may have more malignant potential than differentiated cancer. However, by curative gastrectomy, the elderly patients with undifferentiated advanced gastric cancer can be obtained the equivalent clinical outcome to those with differentiated cancer.

Feasibility of expanded indication for endoscopic submucosal dissection in undifferentiated early gastric cancer

Objective To evaluate the feasibility of expanded indication for endoscopic submucosal dissection (ESD) in undifferentiated early gastric cancer, to investigate the risk factors of lymph node metastasis (LNM), so as to provide the theoretical evidence for the choice of treatment. Methods From June 2007 to December 2018, at the Affiliated Hospital of Qingdao University, the clinical and pathological data of 807 patients with undifferentiated early gastric cancer and undergoing gastrectomy plus lymphadenectomy were retrospectively analyzed. Chi-square test was performed to analyze the correlation between clinicopathologic characteristics of early gastric cancer and LNM. Multivariate logistic regression model was used to analyze the independent risk factor of LNM. Results LNM was found in 17.2% (139/807) patients with undifferentiated early gastric cancer. And no LNM was detected in 110 patients who met the expanded indication of ESD. The results of univariate analysis indicated that LNM was significantly associated with increased carcinoembryonic antigen (CEA), tumour size, gross type, ulcer, invasion depth, lymphovascular invasion and perineural invasion (χ2=4.500, 13.332, 16.611, 6.083, 51.064, 0.564 and 17.006, all P 500 μm ; OR=3.014, 95%CI 1.753 to 5.181, P<0.01) were independent risk factors of LNM in early gastric cancer. Conclusions The expanded ESD indication of undifferentiated early gastric cancer is applicable for endoscopic treatment considering the low risk of LNM. In early undifferentiated gastric cancer, maximum diameter of tumor over 20 mm, lymphovascular invasion, submucosal superficial and deep invasion are the independent risk factors of LNM. Key words: Endoscopic submucosal dissection; Risk factor; Undifferentiated early gastric cancer; Expanded indication; Lymph node metastasis

High Helicobacter pylori Bacterial Load and Low Cytokine Expression Levels Are Associated with Nodular Gastropathy.

Nodular gastropathy (NG) is an inflammatory condition of the gastric mucosa characterized by the endoscopic detection of multiple millimeter protrusions. A strong association between NG and Helicobacter pylori and a possible role of NG as a risk factor for undifferentiated gastric cancer have been described. The aim of this study was to characterize the pathogenic and inflammatory profile of patients with NG. Adult patients referred for upper gastrointestinal endoscopy were prospectively enrolled in this study. H. pylori infection status was determined by rapid urease test. Biopsies were stained with hematoxylin-eosin. Sydney and OLGA scores were used to assess gastritis characteristics and gastric cancer risk. PCR analysis was performed to determine bacterial load and virulence factors CagA (and its EPIYA motifs) and VacA alleles. Finally, gastric mucosa cytokine gene expression (IL-8, IL-1β, and TNF-α) was determined by real-time RT-PCR. Forty-eight patients, mean age of 36years, were recruited. All NG patients were infected by H. pylori. OLGA score was similar in both groups (NG patients and non-NG patients). NG patients had higher bacterial load in the gastric corpus (p = 0.01) and significantly less pro-inflammatory cytokine levels than non-NG infected patients (p = 0.01). In our study, NG is not associated with preneoplastic lesions. An increase in bacterial load without a concomitant increase in mucosal inflammatory cytokine responses in H. pylori-infected subjects with NG may represent a general dampening of immune responses or an additional mechanism of H. pylori active immune evasion.

Prognostic role of ARID1A negative expression in gastric cancer

AT-rich interactive domain 1A (ARID1A) functions as a tumor suppressor and several therapeutic targets in ARID1A-mutated cancers are under development. Here, we investigated the prognostic value of ARID1A for gastric cancer and its association with expression of PD-L1 and p53. ARID1A expression was examined by immunohistochemistry and negative expression of ARID1A was detected in 39 (19.5%) of 200 cases in a test cohort and in 40 (18.2%) of 220 cases in a validation cohort. Negative expression of ARID1A was associated with worse overall survival in undifferentiated cases, particularly early-stage cases. Negative expression of ARID1A was detected in 11 (50%) of 22 PD-L1-positive cases and in 68 (17.1%) of 398 PD-L1-negative cases in a combined cohort. Negative expression of ARID1A was detected in 45 (22%) of 205 p53-positive cases and in 34 (15.8%) of 215 p53-negative cases in a combined cohort. In addition, expression of EZH2, a potential synthetic lethal target in ARID1A-mutated tumors, was detected in 79 ARID1A-negative cases. An ARID1A-knockdown gastric cancer cell line was subjected to microarray analysis, but no actionable targets or pathways were identified. The present results indicate that ARID1A may serve as an early-stage prognostic biomarker for undifferentiated gastric cancer.

1,25-Dihydroxyvitamin D3 affects gastric cancer progression by repressing BMP3 promoter methylation.

BackgroundVitamin D3 has been known to have an anticancer effect, but the mechanisms underlying this is poorly explored. The present study aimed to investigate the antitumor role of vitamin D3 on gastric cancer and mechanisms.MethodsThe Roche Elecsys platform was applied in retrospective studies to detect the role of 25-hydroxylvitamin D3 in adenocarcinoma and colony formation assay was conducted to verify the effect of 1, 25-dihydroxyvitamin D3 on the proliferation of gastric cancer cells. After the identification of hypermethylation of BMP3 CpG islands by bisulfite genomic sequencing (BGS), we further investigated the relationship of BMP3 expression and gastric carcinogenesis by Western blot analysis and gel electrophoresis mobility shift assay (EMSA).ResultsHere we show that low concentration of 1, 25-dihydroxyvitamin D3 links to can-cerization and significantly inhibits proliferation of undifferentiated gastric cancer cell lines SGC-7901 and BGC-823. BMP3 promoter hypermethylation was highly correlated with gastric tumor. Moreover, BMP3 expression was regulated by its promoter methylation in gastric cells. The further exploration of the relationship between 1, 25-dihydroxyvitamin D3 and BMP3 by EMSA results that 1, 25-dihydroxyvitamin D3 stimulates BMP3 expression by the inhibition of BMP3 promoter methylation in gastric tumor cells.ConclusionIn combination with the data from clinical research, bioinformatics analysis and experimental verification, we propose that 1, 25-hydroxylvitamin D3 affects gastric cancer progression by repressing BMP3 promoter methylation.

LXRα Promotes the Differentiation of Human Gastric Cancer Cells through Inactivation of Wnt/β-catenin Signaling.

LXRα is a subtype of the liver X receptors (LXRs). There is accumulating evidence to support the involvement of LXRα in a variety of malignancies. However, the function and specific mechanism of LXRα in gastric cancer (GC) remain unclear. In this study, the expression of LXRα was significantly lower in poorly differentiated and undifferentiated GC tissues compared with well- and moderately differentiated GC tissues by immunohistochemistry analysis. The activation of LXRα leads to the decreased expression of β-catenin, CD44, and Cyclin D1, whereas the inhibition of LXRα has opposite effect. The same results were obtained in animal experiments. Furthermore, results showed that CD44 and Cyclin D1 expression significantly decreased when Wnt/β-catenin signaling was blocked in LXRα silent GC cells, whereas it was significantly increased when Wnt/β-catenin signaling was activated in LXRα over-expressed GC cells. CD44 and Cyclin D1, downstream targets of Wnt/β-catenin signaling, are specific markers for cell differentiation. Therefore, we conclude that LXRα may promote the differentiation of human GC cells through inactivation of Wnt/β-catenin signaling.

MiR-145-5p affects the differentiation of gastric cancer by targeting KLF5 directly.

Krüppel-like factor 5 (KLF5) takes part in the pathologic processes of many types of cancer; however, its expression and roles in the biological behavior of gastric cancer remain unknown. TargetScan suggested that miR-145-5p is the predicted effective and conserved microRNA (miRNA) that binds to KLF5 through its 3'-untranslated region (UTR). We investigated the expression of KLF5 and miR-145-5p messenger RNA (mRNA) in gastric cancer and then analyzed its role in the biological behavior of gastric cancer cells. Our results indicated that KLF5 expression was detected by immunohistochemistry in 39.7% of the gastric cancer cases and was increased compared with that of the corresponding noncancerous normal mucosa (0.01 < p < 0.05). The poorly differentiated subtype showed positive KLF5 expression, whereas the differentiated subtype showed negative KLF5 expression (p < 0.05). Dual-luciferase reporter assay suggested KLF5 3'-UTR was the direct target of miR-145-5p. Compared with the differentiated gastric cancer, miR-145-5p was downregulated in undifferentiated gastric cancer (p < 0.05). The downregulation of KLF5 expression and differentiation of MGC-803 and BGC-823 caused by siKLF5 or miR-145-5p mimic transfection. Our results indicated that miR-145-5p/KLF5 3'-UTR affected the differentiation of gastric cancer. miR-145-5p was able to promote gastric cancer differentiation by targeting KLF5 3'-UTR directly. Our data suggest a novel mechanism for cancer differentiation and a new facet to the role of miR-145-5p/KLF5 in gastric cancer.

Abstract 2510: Clinicopathologic significance of fibroblast growth factor 2 type IIIb and type IIIc in gastric cancer

Abstract [Background]Fibroblast Growth Factor Receptor 2(FGFR2) amplification occuers flequently in undifferentiated gastric cancer(GC), and accounts for 3-10% of primay GC. FGFR2 shows two isoforms, IIIb-type expressed in epithelial cells, and IIIc-type expressed in mesenchymal cells. The aim of this study is evaluating clinicopathological significance of FGFR2-IIIb and IIIc expression on GC cells. [Method]562 patients who had undergone GC surgery were retrospectively examined. Immunohistochemistry of resected specimen was used to investigate the expression of FGFR2-IIIb and IIIc. [Result]FGFR2-IIIb and FGFR2-IIIc were positive in 28 cases (4.9%) and 4 cases (0.7%) of 562 gastric cancers. All of FGFR2-IIIc positive tumors were also positive for FGFR2-IIIb in a same tumor, but both were not positive in same cells. 5-year overall survival rate of FGFR2 positive group is significantly poorer (p=0.0011, log-lank) than that of FGFR2 negative. Moreover, the prognosis of FGFR2-IIIc positive group was significantly poorer (p=0.003, log-lank) than that of FGFR2-IIIb positive group. In univariate analysis, the overall survival was significantly correlated to FGFR2-IIIb positive, FGFR2-IIIc positive, invasion depth, macroscopic type, histological type, lymph node metastasis, peritoneal dissemination, lymphatic invasion, and cytology. In multivariate analysis, FGFR2IIIc was significantly correlated to overall survival (p=0.045) [Conclusion] The expression of FGFR2IIIc and/or FGFR2IIIb was observed in 5% of gastric cancer. FGFR2 amplification is associated with poor overall survival. As a result, treatment targeting FGFR2 amplification has the potential to provide clinical benefit for FGFR2 positive GC. Citation Format: Kenji Kuroda, Masakazu Yashiro, Go Masuda, Yuichiro Miki, Tomohisa Okuno, Shingo Togano, Takahiro Toyokawa, Hiroaki Tanaka, Kazuya Muguruma, Kosei Hirakawa, Masaichi Ohira. Clinicopathologic significance of fibroblast growth factor 2 type IIIb and type IIIc in gastric cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 2510.