Intestinal-type Gastric Cancer Research Articles

Reactivation of CDX2 in Gastric Cancer as Mark for Gene Silencing Memory.

To explore the epigenetic mechanism that reactivates CDX2 (a homeobox transcription factor that serves as a tumor-suppressor gene) in intestinal-type gastric cancer during cancer progression, we examined the methylation status of the CDX2 gene promoter and the expression pattern of methyl-CpG binding protein-2 (MeCP2). From archives of the pathology records of surgically excised advanced stomach cancer cases in the Department of Molecular Pathology, Ehime University in a past decate (n=265), 10 cases of intestinal-type tubular adenocarcinoma, well-differentiated type (wel) with minor poorly-differentiated adenocarcinoma (por) components were selected. The expression pattern of CDX2, MUC2 and MeCP2 in these 10 cases was analyzed by immunohistochemistry. The cancerous and non-cancerous areas were selectively obtained by microdissection, and the methylation status of the CDX2 promoter of each area was assessed by methylation-specific polymerase chain reaction (MSP). In all 10 cases, CDX2 expression was clearly observed in the nucleus of the non-cancerous background of the intestinal metaplasic area, where the unmethylation pattern of the CDX2 gene promoter prevailed with reduced MeCP2 expression. In this metaplastic area, CDX2 expression was co-localized with its target gene, MUC2. CDX2 expression then disappeared from the deep invasive wel area. Reflecting the reduced CDX2 expression, microdissected samples from all the wel areas showed hypermethylation of the CDX2 gene promoter by MSP, with prominent MeCP2 expression. Interestingly, while hypermethylation of the CDX2 gene promoter was maintained in the por area in 8 of the 10 cases, CDX2 expression was restored in por areas where MeCP2 expression was markedly and selectively reduced. The other two cases, however, showed a constant MeCP2 expression level comparable to the surrounding deep invasive wel area with negative CDX2 expression. Therefore, gene silencing by hypermethylation may be overcome by the reduction of methyl-CpG binding proteins, resulting in apparent but non-functional reactivation of CDX2 as a mere molecular mark for gene silencing memory.

From molecular classification to targeted therapeutics: the changing face of systemic therapy in metastatic gastroesophageal cancer.

Histological classification of adenocarcinoma or squamous cell carcinoma for esophageal cancer or using the Lauren classification for intestinal and diffuse type gastric cancer has limited clinical utility in the management of advanced disease. Germline mutations in E-cadherin (CDH1) or mismatch repair genes (Lynch syndrome) were identified many years ago but given their rarity, the identification of these molecular alterations does not substantially impact treatment in the advanced setting. Recent molecular profiling studies of upper GI tumors have added to our knowledge of the underlying biology but have not led to an alternative classification system which can guide clinician's therapeutic decisions. Recently the Cancer Genome Atlas Research Network has proposed four subtypes of gastric cancer dividing tumors into those positive for Epstein-Barr virus, microsatellite unstable tumors, genomically stable tumors, and tumors with chromosomal instability. Unfortunately to date, many phase III clinical trials involving molecularly targeted agents have failed to meet their survival endpoints due to their use in unselected populations. Future clinical trials should utilize molecular profiling of individual tumors in order to determine the optimal use of targeted therapies in preselected patients.

Colon Cancer Associated Transcript-1 (CCAT1) Expression in Adenocarcinoma of the Stomach.

Background: Long non-coding RNAs (lncRNAs) have been shown to have functional roles in cancer biology and are dys-regulated in many tumors. Colon Cancer Associated Transcript -1 (CCAT1) is a lncRNA, previously shown to be significantly up-regulated in colon cancer. The aim of this study is to determine expression levels of CCAT1 in gastric carcinoma (GC).Methods: Tissue samples were obtained from patients undergoing resection for gastric carcinoma (n=19). For each patient, tumor tissue and normal appearing gastric mucosa were taken. Normal gastric tissues obtained from morbidly obese patients, undergoing laparoscopic sleeve gastrectomy served as normal controls (n=19). A human gastric carcinoma cell line (AGS) served as positive control. RNA was extracted from all tissue samples and CCAT1 expression was analyzed using quantitative real time-PCR (qRT-PCR).Results: Low expression of CCAT1 was identified in normal gastric mucosa samples obtained from morbidly obese patients [mean Relative Quantity (RQ) = 1.95±0.4]. AGS human gastric carcinoma cell line showed an elevated level of CCAT1 expression (RQ=8.02). Expression levels of CCAT1 were approximately 10.8 fold higher in GC samples than in samples taken from the negative control group (RQ=21.1±5 vs. RQ=1.95±0.4, respectively, p<0.001). Interestingly, CCAT1 expression was significantly overexpressed in adjacent normal tissues when compared to the negative control group (RQ = 15.25±2 vs. RQ=1.95±0.4, respectively, p<0.001). Tissues obtained from recurrent GC cases showed the highest expression levels (RQ = 88.8±31; p<0.001). Expression levels increased with tumor stage (T4- 36.4±15, T3- 16.1±6, T2- 4.7±1), however this did not reach statistical significance (p=0.2). There was no difference in CCAT1 expression between intestinal and diffuse type GC (RQ=22.4±7 vs. 22.4±16, respectively, p=0.9). Within the normal gastric tissue samples, no significant difference in CCAT1 expression was observed in helicobacter pylori negative and positive patients (RQ= 2.4±0.9 vs. 0.93±0.2, respectively, p=0.13).Conclusion: CCAT1 is up-regulated in gastric cancer, and may serve as a potential bio-marker for early detection and surveillance.

Effects of Two Common Polymorphisms rs2910164 in miR-146a and rs11614913 in miR-196a2 on Gastric Cancer Susceptibility.

Background. Single nucleotide polymorphisms (SNPs) in genes encoding microRNAs may play important role in the development of gastric cancer. It has been reported that common SNPs rs2910164 in miR-146a and rs11614913 in miR-196a2 are associated with susceptibility to gastric cancer. The published results remain inconclusive or even controversial. A meta-analysis was conducted to quantitatively assess potential association between the two common SNPs and gastric cancer risk. Methods. A comprehensive literature search was performed in multiple internet-based electronic databases. Data from 12 eligible studies were extracted to estimate pooled odds ratios (ORs) and 95% confidence intervals (95% CI). Results. C allele of rs2910164 is associated with reduced gastric cancer risk in heterozygote model and dominant model whereas rs11614913 indicates no significant association. Subgroup analysis demonstrates that C allele of rs2910164 and rs11614913 may decrease susceptibility to diffuse type gastric cancer in dominant model and recessive model, respectively, while rs11614913 increased intestinal type gastric cancer in dominant model. Conclusion. SNPs rs2910164 and rs11614913 might have effect on gastric cancer risk in certain genetic models and specific types of cancer. Further well-designed studies should be considered to validate the potential effect.

Helicobacter pylori and microRNAs: Relation with innate immunity and progression of preneoplastic conditions.

The accepted paradigm for intestinal-type gastric cancer pathogenesis is a multistep progression from chronic gastritis induced by Helicobacter pylori (H. pylori) to gastric atrophy, intestinal metaplasia, dysplasia and ultimately gastric cancer. The genetic and molecular mechanisms underlying disease progression are still not completely understood as only a fraction of colonized individuals ever develop neoplasia suggesting that bacterial, host and environmental factors are involved. MicroRNAs are noncoding RNAs that may influence H. pylori-related pathology through the regulation of the transcription and expression of various genes, playing an important role in inflammation, cell proliferation, apoptosis and differentiation. Indeed, H. pylori have been shown to modify microRNA expression in the gastric mucosa and microRNAs are involved in the immune host response to the bacteria and in the regulation of the inflammatory response. MicroRNAs have a key role in the regulation of inflammatory pathways and H. pylori may influence inflammation-mediated gastric carcinogenesis possibly through DNA methylation and epigenetic silencing of tumor suppressor microRNAs. Furthermore, microRNAs influenced by H. pylori also have been found to be involved in cell cycle regulation, apoptosis and epithelial-mesenchymal transition. Altogether, microRNAs seem to have an important role in the progression from gastritis to preneoplastic conditions and neoplastic lesions and since each microRNA can control the expression of hundreds to thousands of genes, knowledge of microRNAs target genes and their functions are of paramount importance. In this article we present a comprehensive review about the role of microRNAs in H. pylori gastric carcinogenesis, identifying the microRNAs downregulated and upregulated in the infection and clarifying their biological role in the link between immune host response, inflammation, DNA methylation and gastric carcinogenesis.

Intratumoral CD68-, CD117-, CD56-, and CD1a-positive immune cells and the survival of Iranian patients with non-metastatic intestinal-type gastric carcinoma

The purpose of this study was to investigate the prognostic significance of intratumoral immune cell counts in Iranian gastric cancer patients.A historical cohort study was conducted on fifty patients with non-metastatic intestinal-type gastric adenocarcinoma who underwent curative gastrectomy during 2004–2008 in Imam-Reza Hospital, Mashhad University of Medical Sciences. Immunohistochemistry (IHC) staining for CD56, CD68, CD117 and CD1a was performed to detect natural killer cells, macrophages, mast cells and Langerhans cells, respectively. The immune cells were counted, and the patients were then stratified into low or high immune cell counts. The prognostic significance of this grouping was analyzed using the Kaplan Meier method and Cox proportional hazards regression modeling.Thirty eight (76%) male and twelve (24%) female patients were enrolled in the study with a mean (±SD) age of 66.0 (±9.2) years. The median survival time was 15.0 (95%CI: 5.5–24.5) months. Natural killer cells, mast cells and Langerhans cells showed a positive effect on survival, whereas the reverse was true for macrophages. Multivariate analysis showed that the independent prognostic factors were location of the tumor (cardia/non-cardia), stage, the presence of extra-cytoplasmic mucin, tumor associated macrophage status (low/high), and tumor associated Langerhans cell status (low/high).In the studied population, gastric carcinoma proved to have a very poor prognosis. Multivariate analysis showed that the prognostic effect of natural killer and mast cells in tumoral tissue were dependent on the Langerhans cell count, defending the theory that dendritic cells mediate other immunocytes activities.

Y-box binding protein 1 is correlated with lymph node metastasis in intestinal-type gastric cancer.

Y-box binding protein-1 (YB-1) is known to modulate gene transcription and protein translation, as well as cellular response to drug treatment. The aim of this study is to correlate YB-1 protein expression levels with clinicopathological parameters in intestinal-type gastric cancer tissue samples (as categorized by the Lauren classification) and substantiate the findings with in vitro experimentation. Paraffin-embedded samples from 167 patients with intestinal-type gastric cancer were used for the construction of tissue microarrays (TMAs). TMA slides were immunostained and YB-1 immunoreactivity score was based on the weighted average intensity score. Univariate analysis revealed that YB-1 immunohistochemical expression was correlated significantly with lymph node status (P = 0.054, borderline significance) and perforation (P = 0.043). YB-1 expression was also found to be an independent predictor of lymph node spread by multivariate analysis. Furthermore, siRNA-mediated YB-1 gene knockdown in MKN7 gastric cancer cells (which is known to originate from an intestinal-type gastric cancer tissue) inhibited cell migration (P = 0.0002) and invasion in vitro (P = 0.0129) significantly. YB-1 expression is associated with lymph node spread in intestinal-type gastric cancer and is a potential prognostic biomarker in this subtype of gastric cancer.

Retrospective Evaluation of the Efficacy of First-Line Treatment of Advanced Gastric Cancer With Docetaxel and Oxaliplatin

The incidence rate of gastric cancer is highest in China, where 5 in 10 new cases of stomach cancer across the world are diagnosed. Even though surgical management is the treatment of choice, it is not significantly effective due to advanced stage of the disease at diagnosis and the increased chances of primary tumor recurrence and metastasis to secondary organs. First-line chemotherapy of advanced gastric cancer patients recommend oxaliplatin and docetaxel; however, not much is known about their usage in Chinese patients. Therefore we retrospectively analyzed 199 cases of advanced gastric cancer (intestinal, diffuse, and mixed types) receiving either docetaxel or oxaliplatin-based first-line chemotherapy. The end-points determined were objective response rate (ORR, sum of complete and partial responses), disease control rate (DCR, sum of complete response, partial response, and stable disease), median progression-free survival (mPFS), and median overall survival (OS) time. Both docetaxel and oxaliplatin-based chemotherapy exhibited improved ORR and DCR; however, the comparison of short-term objective efficacy (ORR and DCR) was not statistically significant (p > .05) between the two groups. Our results indicated that PFS and OS of intestinal-type gastric cancer were extended compared with diffuse-type and mixed-type gastric cancer. Adverse reactions were within the control range and after symptomatic treatment were significantly ameliorated. Both docetaxel and oxaliplatin-based chemotherapy thus had a robust treatment outcome and can prospectively be used as one of the effective chemotherapy regimens for advanced gastric cancer patients in China.

Gastric cancer in three relatives of a patient with a biallelic IL12RB1 mutation.

IL-12Rβ1 deficiency, also known as immunodeficiency 30 (IMD30, OMIM 614891), is a rare immunodeficiency syndrome caused by biallelic mutations in IL12RB1. Three second-degree relatives of a patient with this syndrome, all women, developed intestinal-type gastric cancer (GC). In the Netherlands the incidence of non-cardia GC in women is only 7 per 100,000 person years. Both relatives that were available for testing proved to be heterozygous for the familial IL12RB1 mutation, suggesting there might be a causal relation. Testing 29 index patients from families with early onset and/or a familial history of GC for germline mutations in both IL12RB1 and IL12RB2, that encodes the binding partner of IL-12Rβ1, did not reveal other germline mutations in these genes. Therefore heterozygous inactivating mutations in IL12RB1 and IL12RB2 are unlikely to be frequently involved in GC predisposition. Additional research in families with IL12RB1 mutations is required to determine whether carriers of IL12RB1 mutations have an increased (gastric) cancer risk.

Preneoplastic Conditions in the Stomach: Always a Point of No Return

Gastric atrophy (GA) and intestinal metaplasia are defined preneoplastic conditions of the stomach, whereas Helicobacter pylori gastritis by itself represents a risk condition for gastric cancer (GC) development. After H. pylori eradication, an overall reduction of GC incidence has been shown. However, this effect is lost once H. pylori gastritis has evolved to severe GA. On the other hand, only up to 5% of patients with severe GA may develop intestinal-type GC, and therefore the so-called ‘point of no return' may not be appropriate to define the condition of all patients carrying preneoplastic changes in the gastric mucosa. Patients with the highest risk for GC are those who have already had GC that was cured by endoscopic resection. Prospective trials on the effect of H. pylori eradication in this high-risk group of patients showed inconsistent results, probably because of the inclusion of patients with and without baseline severe GA. Severe fundic GA determined by means of histology or serology represents the condition with the highest risk for metachronous neoplastic lesions in the stomach. In the present review, we focus on the effects of H. pylori eradication in patients with severe atrophy in terms of GC prevention.

Spatially defined microsatellite analysis reveals extensive genetic mosaicism and clonal complexity in intestinal metaplastic glands.

Intestinal metaplasia (IM) has been recognized as the first irreversible precancerous stage of intestinal-type gastric cancer at which genetic instabilities, such as microsatellite (MS) instability and loss of heterozygosity, can already be detected. However, the extent and clonal relationship of these genetic lesions in the precancerous tissues are not fully appreciated. In this work, we have used well established MS markers to analyze the relatedness of spatially separated individual metaplastic glands as well as subsegments within single glands from the same patients. We found that individual IM glands frequently show different marker lengths even for closely apposed IM glands, suggesting that these tissues have already gained the ability to independently evolve their genome regardless of whether or not they share a common origin. Furthermore, within individual IM glands, there is also significant intra-gland diversity in the MS markers. Since most of these cells are not dividing and only have a limited lifespan, this result indicates that in each IM gland, a single dominant clone is rare and new clones are constantly created by either progenitor cells or stem cells. This greatly enhanced ability to create de novo genetic alterations may underlie the importance of this stage in the eventual progression toward cancer. Given the widely observed phenotype switch in the early stages of many solid tumors, whether this associated genetic stability is also an intrinsic property of metaplastic transformation should be extensively characterized to further our understanding of cancer initiation.

Genetic variation in C12orf51 is associated with prognosis of intestinal-type gastric cancer in a Chinese population

Recent genome-wide association study (GWAS) on esophageal squamous-cell carcinoma (ESCC) among Chinese population has identified two novel single nucleotide polymorphisms (SNPs) rs11066280 and rs2074356 on C12orf51 gene. We hypothesized that SNPs rs11066280 and rs2074356 could influence gastric cancer survival outcomes. We genotyped the SNPs rs11066280 and rs2074356 in 940 patients with surgically resected gastric cancer. Analyses of genotype association with survival outcomes were assessed by the Kaplan-Meier method, Cox proportional hazards models and the log-rank test. There was no significant association between rs11066280 and survival of gastric cancer. However, in the stratification analysis of histology, we found that the rs11066280 TA/AA genotypes were associated with a poor survival of intestinal-type gastric cancer (log-rank P=0.041, hazard ratio [HR]=1.40, 95% confidence interval [CI]=1.02–1.93), Moreover, this hazardous effect was more prominent among patients with tumor size>5cm, no distant metastasis, chemotherapy and drinking. No significant association was observed between rs2074356 and the survival of gastric cancer. C12orf5 rs11066280 could be useful marker of survival assessment and individualized clinical therapy for gastric cancer, particularly among the intestinal-type gastric cancer.

A genetic variant of miR-148a binding site in the SCRN1 3'-UTR is associated with susceptibility and prognosis of gastric cancer.

Single nucleotide polymorphisms (SNPs) in the 3′-untranslated regions targeted by putative mircoRNA can change its binding strength, affecting the susceptibility and prognosis of cancer. We aimed to investigate the associations between SNPs within miR-148a binding sites and gastric cancer (GC) risk and prognosis. Using bioinformatics tools, we selected two SNPs (SCRN1 rs6976789 and PDYN rs2235749) located in miR-148a target sites. We genotyped the two SNPs in a case-control study comprising 753 GC patients and 949 cancer-free subjects. We found a significantly increased risk of GC associated with the SCRN1 rs6976789 C>T polymorphism [adjusted OR = 1.25, 95% confidence interval (CI) = 1.02–1.53; CT/TT vs. CC]. However, no significant association was found between the PDYN rs2235749 and GC risk in all genetic models. Furthermore, we evaluated whether SCRN1 rs6976789 affected the survival of GC patients. Results showed that individuals with SCRN1 rs6976789 TT genotype had poorer overall survival compared with those carried CC/CT genotypes in intestinal-type GC (adjusted HR = 2.47, 95% CI = 1.21–5.05). Luciferase report assay showed that the rs6976789 variant T allele influenced the binding ability of miR-148a. Our results suggested that the SCRN1 rs6976789 polymorphism may play an important role in the GC development and progression.

Lauren classification combined with HER2 status is a better prognostic factor in Chinese gastric cancer patients.

BackgroundLauren-classification and human epidermal growth factor receptor 2 (HER2) status are two important pathological features of gastric cancer patients. The prognostic value of HER2 in gastric cancer remains controversial. Intestinal type gastric cancer has better prognosis and higher HER2 positive proportion. What is the interaction between these two factors? We hypothesized that a combination of Lauren-classification and human epidermal growth factor receptor 2 (HER2) status (L-H status) might be more meaningful than either factor alone.MethodsWe collected 838 gastric cancer patients at all stages who had received treatment in our cancer center. This study was registered in the website of ClinicalTrials.Gov, with the number NCT01927146. We divided the patients into six groups according to their L-H status: Group A, HER2 negative and intestinal type; Group B, HER2 positive and intestinal type; Group C, HER2 negative and diffuse type; Group D, HER2 positive and diffuse type; Group E, HER2 negative and mixed type; and Group F, HER2 positive and mixed type.ResultsDiffuse type and intestinal type accounted for 51.0% and 33.9%, respectively. The proportion of HER2 positive patients was 11.2%, 25.4%, 2.1% and 10.2% in the whole patient group, intestinal, diffuse and mixed type, respectively. Median overall survival was 34.0 months, 25.3 months, 27.6 months, 19.2 months, 25.9 months and 26.4 months in the six groups patients, P = 0.053. There was a significant difference in survival among the first four groups (P < 0.001). HER2 was an independent prognostic factor in the intestinal type and in stage I + II patients, but not in the diffuse type or stage III + IV patients. L-H status was an independent prognostic factor in patients at all stages. For the diffuse and intestinal types, the multivariate analysis showed that HER2 was not an independent prognostic factor, while Lauren classification and L-H status were. Moreover, L-H status was a better prognostic factor than the Lauren classification.ConclusionsL-H status is a prognostic factor in diffuse and intestinal type patients, but not in the mixed type. Patients with HER2 negative and intestinal type had the best survival, while patients with HER2 positive status and diffuse type had the worst survival.

Integrins αvβ3 and αvβ5 as prognostic, diagnostic, and therapeutic targets in gastric cancer.

BackgroundWe investigated the expression of two αv integrins, αvβ3 and αvβ5, in gastric cancer (GC) by testing the following hypotheses: that these molecules are expressed in GC; that they are implicated in GC biology; that they help to distinguish between the two major histological subtypes of GC, according to Laurén; and that they are prognostically relevant.MethodsFormalin-fixed and paraffin-embedded tissue samples from 482 GC samples were stained immunohistochemically using rabbit monoclonal antibodies directed against αvβ3 (EM22703) and αvβ5 (EM09902). Immunostaining of tumor, stroma, and endothelial cells was evaluated separately by the quantity and intensity, generating an immunoreactivity score. The immunoreactivity score of both antibodies was correlated with clinicopathology data and patient survival.ResultsEach integrin was expressed in at least one tumor component in all GCs. Both were expressed significantly more often in the intestinal phenotype according to Laurén. Moreover, patients who grouped as “positive” for expression of αvβ3 on endothelial cells, and patients with an intestinal type GC, grouped as “negative” for expression of αvβ5 on stroma cells, had significantly longer survival. The expression of αvβ5 on stroma cells was confirmed to be an independent prognostic factor of intestinal-type GC.ConclusionThe expression of αvβ3 and αvβ5 in at least one tumor component in all GC samples is an interesting new result that should form a basis for further investigations; for example, regarding selective integrin antagonists and the value of αvβ3 and αvβ5 as putative prognostic biomarkers. Moreover, both markers might be helpful in the routine classification of GC subtypes.Electronic supplementary materialThe online version of this article (doi:10.1007/s10120-014-0435-2) contains supplementary material, which is available to authorized users.

Abstract 47: Y-box binding protein 1 is correlated with lymph node metastasis in intestinal type of gastric cancer

Abstract Gastric cancer still ranks among the top ten most common cancer in the world, despite a declining trend in incidence. The multifunctional protein Y Box Binding Protein-1 (YB-1) is known to regulate transcription, translation, DNA repair and cellular response to drug treatment. This study evaluated the correlation between YB-1 protein expression levels with clinico-pathological characteristics in the intestinal type of gastric cancer, which was further validated with in vitro experimentation. Tissue microarrays (TMAs) were constructed from specimens obtained from 167 patients diagnosed with intestinal gastric cancer. Immunohistochemical analysis of the YB-1 protein was performed on the TMAs . The intensity of YB-1 staining in the intestinal type of gastric cancer was scored as absent to strong staining and the percentage of YB-1 immunostained cells was determined. YB-1 immunoreactivity was based on the weighted average intensity (WAI) for each specimen, which was calculated as the sum of percentages of stained cells for each intensity divided by the total percentage of stained cells. siRNA-mediated silencing of the YB-1 gene in MKN7 intestinal gastric cancer cells was verified by RT-PCR. Cell migration and invasion assays were carried out using commercially available kits. YB-1 immunostaining was present in all the cancer tissue samples examined. The YB-1 protein was observed to be predominantly expressed in the cytoplasm of the gastric cancer cells. Univariate analysis revealed that YB-1 immunohistochemical expression was significantly correlated with lymph node status and perforation. However, multivariate analysis showed that only YB-1 protein expression is an independent predictor of lymph node spread. Down-regulation of the YB-1 gene expression in MKN7 cells significantly inhibited cell migration and invasion, processes which are important in the metastatic cascade. The findings suggest that YB-1 expression is associated with metastasis in the intestinal type of gastric cancer and is a potential prognostic biomarker and therapeutic target in this subtype of gastric cancer. Citation Format: TianTian Guo, Yingnan Yu, George Wai-Cheong Yip, Gyeong Hun Baeg, Aye Aye Thike, Puay-Hoon Tan, Ken Matsumoto, Boon Huat Bay. Y-box binding protein 1 is correlated with lymph node metastasis in intestinal type of gastric cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 47. doi:10.1158/1538-7445.AM2014-47

Abstract 546: CD44 variant expression is a poor prognostic marker in early gastric cancer and well-differentiated gastric cancer

Abstract The present study is to investigate the significance of the expression of CD44 variant (CD44v), a functional cancer stem cell marker, in the primary gastric cancer. We first tested whether CD44v is selectively expressed in gastric cancer tissue. With the tissue microarray samples containing the 6 normal tissue, 6 H. pylori associated gastritis, 12 intestinal metaplasia, 12 low-grade adenoma, 12 high-grade adenoma, 25 early gastric cancer and 26 advanced gastric cancer. The positive expression rates in tumor were 65.3% (49/75) whereas the positive rates in normal and gastritis tissue were 30.4% (p = 0.003). Next, we investigated the clinical significance of gastric cancer with the tissue microarray containing 333 gastric cancer tissue derived from the patients who underwent radical gastrectomy for gastric cancer from 1999 to 2007. The positive expression rates of CD44v (55%, 134/242) were higher in intestinal type gastric cancer than in diffuse type (28%, 21/76). Intestinal type gastric cancer among the CD44v-positive gastric cancer accounted for 82% (134/164). The 5-year survival rate of CD44v-positive gastric cancer was 67.7% whereas that of CD44v-negative gastric cancer was 62.9%. The survival difference was higher as time passed, but it was statistically insignificant (p = 0.219). However, in the subgroup analysis we found that the survival differences were significantly higher in early gastric cancer and well-differentiated gastric cancer (p = 0.013, 5-YSR ; p = 0.046, 5-YSR , respectively). We also investigated the correlation between the expressions of CD44v and EGFR along with the well-known proliferative molecular biomarkers, cylin D1 and Ki-67. Only the expression of Ki-67 were some correlation with CD44v expression in gastric cancer; CD44v-positive rates of the cancers with negative or 1 positive Ki-67 expression were 37% (47/127) whereas those with 2 or 3 positive Ki-67 expression were 57.4% (116/202). This study demonstrates that CD44v can be a good biomarker for early gastric cancer and well-differentiated gastric cancer. [This study was supported by a grant from the National R&amp;D Program for Cancer Control, Ministry for Health, Welfare &amp; Family Affairs, Republic of Korea. (0820050).] Citation Format: Won Sup Lee, Se-Il Go, Jeong-Hee Lee, Sang-Ho Jeong, Young-Joon Lee, Soon Chan Hong, Woo Song Ha, Gyung Hyuck Ko. CD44 variant expression is a poor prognostic marker in early gastric cancer and well-differentiated gastric cancer. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 546. doi:10.1158/1538-7445.AM2014-546

Abstract 2209: Effects of IL10 haplotypes and atomic bomb radiation exposure on risks of gastric cancer subtypes

Abstract Background: Gastric cancer is one of the cancers whose risks of incidence and mortality clearly increased among Japanese atomic-bomb (A-bomb) survivors. Gastric cancer incidence in the Radiation Effects Research Foundation's (RERF) Life Span Study cohort population increased with radiation dose and remains high even today, more than 65 years since exposure. In this study, we specifically examined the association between risk of gastric cancer (intestinal and diffuse types) and radiation exposure by haplotypes of the immunosuppressive gene IL10 to investigate inter-individual differences in gastric cancer susceptibility associated with radiation exposure. Methods: We analyzed the follow-up data from the RERF Immunogenome Study Cohort of 4,690 A-bomb survivors at baseline covering 1981-2005: a total of 200 gastric cancer cases comprising 93 intestinal-type, 96 diffuse-type, and 11 other subtypes. Relative risk (RR) for IL10 and excess relative risk (ERR) for radiation of gastric cancer subtypes were estimated. Using a single haplotype block composed of four haplotype-tagging single nucleotide polymorphisms (comprising major haplotype allele IL10-ATTA and minor haplotype allele IL10-GGCG), multiplicative and additive models for joint effects of radiation and this IL10 haplotyping were examined. Results: The RR of intestinal-type gastric cancer among A-bomb survivors harboring the minor homozygote was significantly high, being 2.2 (95% confidence interval (CI): 1.1-4.3), compared to those harboring the major homozygote. In other words, the IL10 minor haplotype allele was considered to be a risk factor for intestinal-type gastric cancer. However, no significant association was observed between radiation exposure and intestinal-type gastric cancer, and no statistical interaction was observed between radiation exposure and IL10 haplotypes. The IL10 minor haplotype allele was not a risk factor for diffuse-type gastric cancer. The ERR per Gy of radiation exposure by haplotype showed statistical significance only for the major homozygote (0.46/Gy, 95% CI: 0.02-1.4). On the other hand, the ERR per Gy for the minor homozygote was close to 0, with no statistical significance. Therefore, the IL10 minor haplotype allele might act to suppress the radiation-associated risk elevation of diffuse-type gastric cancer. Conclusion: This study of A-bomb survivors suggests that IL10 haplotypes may be associated with the development of radiation-related diffuse-type gastric cancer. There is a possibility, therefore, that immune/inflammatory-related gene polymorphisms may be involved in inter-individual differences in radiation-related cancer risks. Further studies based on genome-wide association analysis are currently underway. Citation Format: Tomonori Hayashi, John B. Cologne, Yiqun Hu, Kengo Yoshida, Waka Ohishi, Ikue Hayashi, Junko Kajimura, Seishi Kyoizumi, Yoichiro Kusunoki, Kei Nakachi. Effects of IL10 haplotypes and atomic bomb radiation exposure on risks of gastric cancer subtypes. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2209. doi:10.1158/1538-7445.AM2014-2209

209: STAT3-driven regulation of microRNAs during gastric inflammation-associated tumourigenesis

Hyperactivation of the latent transcription factor signal transducer and activator of transcription (STAT)3 is frequently observed in inflammation-associated gastric cancer. However the full spectrum of downstream gene networks modulated by STAT3 during the pathogenesis of gastric tumourigenesis remains ill-defined. The gp130 F / F gastric cancer mouse model which recapitulates the hyperactive STAT3 signaling and tumor progression observed in human disease was therefore employed to identify novel STAT3-regulated microRNAs (miRNAs) associated with the onset of gastric tumours. Using a miRNA array approach coupled with miRNA real-time quantitative PCR validation, we identified that 2 miRNAs (miR-146b and miR-429) are consistently up in stomach tissue from gp130 F / F mice at 4 weeks (prior to tumour initiation) and 3 months (established tumour formation) of age compared to age-matched wild type mice. Consistent with our previous demonstration that interleukin (IL)-11/STAT3 signaling plays a causal role during gastric tumourigenesis in gp130 F / F mice, normalization of gastric STAT3 activation and IL-11 expression in gp130 F / F mice lacking the IL-11 ligand-binding receptor subunit (IL-11Ra) also normalized the expression of these miRNAs. We also found that in response to IL-11 treatment of wild-type mice, miR-146b and miR-429 are significantly increased along with STAT3 activation. Furthermore, these 2 miRs are upregulated in human intestinal-type gastric cancer biopsies characterized by increased STAT3 signaling. Collectively, our data reveal 2 novel STAT3-regulated miRNAs in gastric tumourigenesis, and therefore suggest that the regulation of specific miRNAs may represent an additional mechanism by which STAT3 promotes oncogenesis in the stomach.

150: Haematopoietic cell kinase activation promotes IL-11 dependent gastric cancer progression and invasion in mice

Gastric cancer has a high mortality rate associated with its late stage diagnosis. Although Gp130 knock-in mutant mice (gp130 F / F ) develop benign gastric tumours dependent upon IL-11-induced Stat3/mTORC activation with hallmarks of early stage intestinal-type gastric cancer in humans [1] , [2] , there is an urgent need to develop mouse models that mimic the progression from adenoma to carcinoma and metastasis. Macrophages are a major component of the tumour micro-environment, and their increased numbers and alternative activation is commonly associated with tumour progression and metastasis. Haematopoietic Cell Kinase (Hck) is a myeloid-specific Src family kinase that is involved in polarization of alternatively activated macrophages, which correlate with a poor prognosis for human gastric cancer. To establish whether aberrant Hck activation would induce tumourigenesis, Hck mutant mice that exhibit constitutive kinase activation (Hck Up / Up ) were crossed with gp130 F /+ mice that are predisposed to gastric tumour development. Surprisingly, the resulting gp130 F /+ ;Hck Up / Up compound mutants developed tumours similar to gp130[F/F] animals, while gp130 F /+ mice remained tumour-free. Furthermore, tumours in 9 month old gp130 F /+ ;Hck Up / Up mutants showed sub-mucosal invasion, which was not observed in gp130 F / F mice. Western blotting and immunohistochemical analysis revealed a significant increase in tumour cell proliferation in gp130 F /+ ;Hck Up / Up mutants compared to gp130 F / F animals, consistent with an increased abundance of the activated forms of Stat3, Erk, Akt and S6 cytoplasmic signalling proteins. While the total number of macrophages remained unaffected, qPCR analysis of purified tumour-associated macrophages from gp130 F /+ ; Hck Up / Up mice showed a significant increase in markers of alternative macrophage activation, including Il4 , Il13 , Arg1 and Ym1 when compared to cells from gp130 F / F animals. Furthermore, reciprocal adoptive transfer of Hck Up / Up bone-marrow into gp130 mutant recipients was sufficient to increase tumour burden and promote alternative macrophage polarisation. Collectively, our results demonstrate that aberrant Hck activation promotes polarisation towards alternative macrophage activation and confers an invasive gastric cancer phenotype.