Mucosal Gastric Cancer Research Articles

Microfluidic device featuring micro-constrained channels for multi-parametric assessment of cellular biomechanics and high-precision mechanical phenotyping of gastric cells

BackgroundCellular biomechanics plays a significant role in the regulation of cellular physiological and pathological processes. In recent years, multiple methods have been developed to evaluate cellular biomechanics, such as atomic force microscopy (AFM), micropipette aspiration, and magnetic tweezers. However, most of these methods only focus on a single parameter and cannot automate the process at a high-efficiency level. A novel microfluidic method is necessary to achieve the simultaneous multi-parametric measurement of cellular biomechanics and high-precision cellular mechanical phenotyping at high throughput. ResultsTo tackle the issue concerning the low-throughput and cellular single-parameter evaluation, we designed and fabricated a microfluidic chip featuring multiple micro-constrained channels structure, providing a simultaneous multi-parametric assessment of cellular biomechanics, including elastic modulus, recovery capability, and deformability. We compared the biomechanical properties of normal human gastric mucosal epithelial cells (GES-1) and human gastric cancer cells (AGS and MKN-45) by the chip. Results demonstrated that the elastic modulus of GES-1, AGS, and MKN-45 cells decreased sequentially, which was the opposite of their invasiveness and metastasis potential, suggesting the inverse correlation between cellular elastic modulus and malignancy. Meanwhile, the recovery capability and deformability of GES-1, AGS, and MKN-45 cells increased sequentially, demonstrating the positive correlation between cellular deformability and malignancy. Furthermore, multiple parameters were used to distinguish gastric cancer cells from normal gastric cells via machine learning. An accuracy of over 94.8% for identifying gastric cancer cells was achieved. SignificanceThis study provides a deep insight into the biophysical mechanism of gastric cancer metastasis at the single-cell level and possesses great potential to function as a valuable tool for single-cell analysis, thereby facilitating high-precision and high-throughput discrimination of cellular phenotypes that are not easily discernible through single-marker analysis.

RNA expression of 6 genes from metastatic mucosal gastric cancer serves as the global prognostic marker for gastric cancer with functional validation

BackgroundMolecular analysis of advanced tumors can increase tumor heterogeneity and selection bias. We developed a robust prognostic signature for gastric cancer by comparing RNA expression between very rare early gastric cancers invading only mucosal layer (mEGCs) with lymph node metastasis (Npos) and those without metastasis (Nneg).MethodsOut of 1003 mEGCs, all Npos were matched to Nneg using propensity scores. Machine learning approach comparing Npos and Nneg was used to develop prognostic signature. The function and robustness of prognostic signature was validated using cell lines and external datasets.ResultsExtensive machine learning with cross-validation identified the prognostic classifier consisting of four overexpressed genes (HDAC5, NPM1, DTX3, and PPP3R1) and two downregulated genes (MED12 and TP53), and enabled us to develop the risk score predicting poor prognosis. Cell lines engineered to high-risk score showed increased invasion, migration, and resistance to 5-FU and Oxaliplatin but maintained sensitivity to an HDAC inhibitor. Mouse models after tail vein injection of cell lines with high-risk score revealed increased metastasis. In three external cohorts, our risk score was identified as the independent prognostic factor for overall and recurrence-free survival.ConclusionThe risk score from the 6-gene classifier can successfully predict the prognosis of gastric cancer.

A case of chronic gastric anisakiasis coexisting with early gastric cancer.

Anisakiasis is a parasitic disease caused by the consumption of raw or undercooked fish that is infected with Anisakis third-stage larvae. In countries, such as Japan, Italy, and Spain, where people have a custom of eating raw or marinated fish, anisakiasis is a common infection. Although anisakiasis has been reported in the gastrointestinal tract in several countries, reports of anisakiasis accompanied by cancer are rare. We present the rare case of a 40-year-old male patient with anisakiasis coexisting with mucosal gastric cancer. Submucosal gastric cancer was suspected on gastric endoscopy and endoscopic ultrasonography. After laparoscopic distal gastrectomy, granulomatous inflammation with Anisakis larvae in the submucosa was pathologically revealed beneath mucosal tubular adenocarcinoma. Histological and immunohistochemical investigation showed cancer cells as intestinal absorptive-type cells that did not produce mucin. Anisakis larvae could have invaded the cancer cells selectively because of the lack of mucin in the cancerous epithelium. Anisakiasis coexisting with cancer is considered reasonable rather than coincidental. In cancer with anisakiasis, preoperative diagnosis may be difficult because anisakiasis leads to morphological changes in the cancer.

Ball Valve Syndrome Treated by Endoscopic Submucosal Dissection.

An 85-year-old female was diagnosed with cerebellar hemorrhage based on computed tomography (Figure A). She underwent a craniotomy to remove the hematoma. It has been 2 months since she started rehabilitation after the craniotomy but she still experiences repeated vomiting. Therefore, gastrointestinal transit disorders were considered a differential diagnosis. An esophagogastroduodenoscopy was performed for a detailed examination, which revealed an erythematous, mobile, and semi-pedunculated lesion approximately 40 mm in size near the pyloric ring in the gastric antrum. The lesion was entrapped in the duodenal bulb (Figure B and Figure C). With a diagnosis of early gastric cancer resulting in ball valve syndrome, endoscopic submucosal dissection was performed for symptom relief. A pathological examination demonstrated that the tumor was a mucosal gastric cancer and had been completely resected with free vertical and horizontal margins (Figure D and Figure E). The patient tolerated a progressive diet with no recurrence of vomiting after treatment. Although repeated vomiting is often an aftereffect of cerebrovascular disease, gastrointestinal transit disorders should be considered as possible causes in cases of persistent vomiting because elderly patients are also at the risk of the development of gastrointestinal neoplasms. Endoscopic submucosal dissection was effective for the treatment of ball valve syndrome caused by gastric cancer. We thank Natsuko Nakano for the pathological examination and Yo Matsui for the radiological diagnosis.

Combining Raman spectroscopy and machine learning to assist early diagnosis of gastric cancer

Gastric cancers, with gastric adenocarcinoma (GAC) as the most common histological type, cause quite a few of deaths. In order to improve the survival rate after GAC treatment, it is important to develop a method for early detection and therapy support of GAC. Raman spectroscopy is a potential tool for probing cancer cell due to its real-time and non-destructive measurements without any additional reagents. In this study, we use Raman spectroscopy to examine GAC samples, and distinguish cancerous gastric mucosa from normal gastric mucosa. Average Raman spectra of two groups show differences at 750 cm−1, 1004 cm−1, 1449 cm−1, 1089–1128 cm−1, 1311–1367 cm−1 and 1585–1665 cm−1, These peaks were assigned to cytochrome c, phenylalanine, phospholipid, collagen, lipid, and unsaturated fatty acid respectively. Furthermore, we build a SENet-LSTM model to realize the automatic classification of cancerous gastric mucosa and normal gastric mucosa, with all preprocessed Raman spectra in the range of 400–1800 cm−1 as input. An accuracy 96.20% was achieved. Besides, by using masking method, we found the Raman spectral features which determine the classification and explore the explainability of the classification model. The results are consistent with the conclusions obtained from the average spectrum. All results indicate it is potential for pre-cancerous screening to combine Raman spectroscopy and machine learning.

Clinicopathological and molecular characterization of early gastric adenocarcinoma in Helicobacter pylori-uninfected patients: emphasis on differentiated gastric adenocarcinoma.

Recently, Helicobacter pylori (HP)-uninfected gastric mucosal cancer has been reported; however, the clinicopathological and molecular features of HP-uninfected gastric cancer have not been elucidated. We evaluated the clinicopathological, immunohistochemical, and genetic alterations in HP-uninfected early gastric adenocarcinoma using next-generation sequencing (NGS). Among 968 primary early gastric carcinomas, 64 (6.6%) were HP-uninfected gastric adenocarcinoma and were pathologically classified as gastric adenocarcinoma of fundic-gland type (GA-FG, n = 39), differentiated gastric adenocarcinoma (DGA, n = 16), and signet-ring cell carcinoma (SRCC, n = 9). Based on the expression profile of the mucin core protein, DGAs were classified into a gastrointestinal phenotype showing either MUC5AC or MUC6 expression and MUC2 or CD10 expression simultaneously (n = 5), and a gastric phenotype (n = 11) showing either MUC5AC or MUC6 expression. All DGAs with a gastrointestinal phenotype shared similar endoscopic characteristics, such as reddish depressed lesions in the antrum. In contrast, DGAs with a gastric phenotype exhibited several distinct endoscopic features, including a raspberry-shaped appearance and whitish flat-elevated appearance; the former expressed only MUC5AC and the latter exhibited co-expression of MUC5AC and MUC6. Among 16 HP-uninfected DGAs, seven were subjected to NGS. APC was recurrently mutated in DGA (42.9%) and was enriched in DGAs with a gastrointestinal phenotype (75%). Overall, HP-uninfected gastric adenocarcinomas showed distinct clinicopathologic and endoscopic characteristics. Furthermore, HP-uninfected DGAs, especially those with a gastrointestinal phenotype, may be characterized by recurrent APC mutations.

Meta-analysis of mucosal microbiota reveals universal microbial signatures and dysbiosis in gastric carcinogenesis

The consistency of the associations between gastric mucosal microbiome and gastric cancer across studies remained unexamined. We aimed to identify universal microbial signatures in gastric carcinogenesis through a meta-analysis of gastric microbiome from multiple studies. Compositional and ecological profiles of gastric microbes across stages of gastric carcinogenesis were significantly altered. Meta-analysis revealed that opportunistic pathobionts Fusobacterium, Parvimonas, Veillonella, Prevotella and Peptostreptococcus were enriched in GC, while commensals Bifidobacterium, Bacillus and Blautia were depleted in comparison to SG. The co-occurring correlation strengths of GC-enriched bacteria were increased along disease progression while those of GC-depleted bacteria were decreased. Eight bacterial taxa, including Veillonella, Dialister, Granulicatella, Herbaspirillum, Comamonas, Chryseobacterium, Shewanella and Helicobacter, were newly identified by this study as universal biomarkers for robustly discriminating GC from SG, with an area under the curve (AUC) of 0.85. Moreover, H. pylori-positive samples exhibited reduced microbial diversity, altered microbiota community and weaker interactions among gastric microbes. Our meta-analysis demonstrated comprehensive and generalizable gastric mucosa microbial features associated with histological stages of gastric carcinogenesis, including GC associated bacteria, diagnostic biomarkers, bacterial network alteration and H. pylori influence.

Helicobacter Pylori Infection Among Patients Undergoing Upper Gastrointestinal Endoscopy For Dyspepsia

Introduction: Helicobacter pylori is associated with the pathogenicity of gastroduodenal mucosal lesions, ulcers, and gastric cancers. The present study was undertaken to study the prevalence of H. pylori infection among patients undergoing upper gastrointestinal (UGI) endoscopy for dyspepsia in the Nepalese population. Methods: A cross-sectional, hospital-based study was conducted among patients presenting with dyspepsia. Each study patient underwent upper gastrointestinal endoscopy followed by a rapid urease test or histopathology from the biopsy sample for H. pylori detection. Data analysis was done by SPSS 20. Results: The mean age of the patients was 43±11.65 years (M: F=1.4:1) with male predominance. The prevalence of H. pylori infection was 53.2% among the dyspeptic patients undergoing UGI endoscopy. The H. pylori infection was significantly associated with gastritis, duodenitis, gastric ulcer, duodenal ulcer, and gastric cancer (p <0.05). Conclusion: This study demonstrates a high prevalence of H. pylori among patients undergoing UGI endoscopy for dyspepsia.

Magnifying endoscopy for the diagnosis of early gastric cancer: Establishment of technique, diagnostic system, and scientific evidence from Japan

Magnifying endoscopy for the diagnosis of early gastric cancer: Establishment of technique, diagnostic system, and scientific evidence from Japan

Helicobacter pylori infection is associated with the co-occurrence of bacteria in the oral cavity and the gastric mucosa.

Pathogens capable of impacting gastrointestinal tract tumor development are located in the oral cavity, but whether these oral bacteria are able to colonize the gastric mucosa in gastric cancer (GC) patients and whether Helicobacter pylori infection can influence this process remains to be established. Microbial 16S rDNA deep sequencing was conducted to characterize bacteria present in paired gastric mucosa and tongue coating samples in 27 patients with superficial gastritis (SG) and 11 GC patients. While the overall composition of the gastric mucosa and tongue coating microbiomes differed substantially, certain bacteria were present in both of these communities. The co-occurrence of bacteria between the tongue coating and gastric mucosa differed significantly between SG and GC patients. Of the 15 most abundant shared oral bacteria genera (the core shared oral bacteria), which were associated with differences in microbiota composition between these tongue coating and gastric mucosa, three were enriched in the gastric mucosa of GC patients relative to SG patients, whereas, 12 were depleted in GC patient samples. Furthermore, the prevalence and relative abundance of these core shared oral bacteria in the gastric mucosa were also linked to H.pylori infection status, and the core shared oral bacteria were also associated with the overall composition of the gastric mucosal microbiome. Helicobacter pylori infections are linked to the co-occurrence of bacteria in the oral microbiome and the gastric mucosal microbiome. Ectopic colonization of oral microbes may be a primary driver of H.pylori-induced gastric microbial dysbiosis in patients with GC.

MiR-212 as potential biomarker suppresses the proliferation of gastric cancer via targeting SOX4.

BackgroundCirculating microRNAs that post‐transcriptionally regulate gene expressions have been reported as promising biomarkers in cancer monitoring. This study was to identify the potential role of circulating miR‐212 in gastric cancer and whether it could serve as a novel biomarker for gastric cancer.MethodsWe detected the serum levels of miR‐212 in 100 health people and 110 gastric cancer patients and analyzed the relationships of the serum level of miR‐212 with gastric cancer. We detected the expression of miR‐212 in human gastric mucosal epithelial cell line (GES‐1) and human gastric cancer cell lines (NCI‐N87 and SNU‐16) using qRT‐PCR. Then, we detected the role of 5‐aza‐deoxycytidine on the epigenetic regulation of miR‐212 in human gastric cancer cell lines. Furthermore, luciferase reporter assay was used to detect binding activity of miR‐212 on SOX4 mRNA, and their functions on the cell proliferation and apoptosis.ResultsThe expression of miR‐212 was higher in health people than that in gastric cancer patients, higher in gastric mucosal epithelial cell line than that in gastric cancer cells. miR‐212 can be a circulating biomarker and an independent prognostic factor of gastric cancer. Moreover, miR‐212 can directly regulate the 3′UTR of SOX4 mRNA to suppress p53 and Bax, resulting gastric cancer cells proliferation inhibition and apoptosis induction.ConclusionOur study demonstrated that miR‐212 was epigenetically downregulated in gastric cancer, and resulting low level of miR‐212 can be a potential circulating biomarker and poor prognosis predicator of gastric cancer.

Integrated Profiling Revealed Potential Regulatory Networks Among Long Noncoding RNAs and mRNAs in Mucosal Gastric Cancer.

Gastric cancer is one of the most commonly occurring cancers worldwide. Investigation of long noncoding RNAs is of increasing interest, particularly in relation to their contribution to progression and prognosis of gastric cancers; however, insufficient studies been performed investigating the part of long noncoding RNAs play in gastric cancer carcinogenesis. Patterns of dysregulated long noncoding RNA and messenger RNA between mucosa gastric cancer and adjacent normal tissues were identified using long noncoding RNAs microarray analysis. Quantitative real-time polymerase chain reaction was conducted as a means to verify the obtained data. Both Gene Ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analyses were subsequently used to investigate the function of dysregulated long noncoding RNAs and messenger RNAs. Cis and trans action was used to predict the possible targets of long noncoding RNAs, and a coexpression network was created to simulate the complex intergenic interactions. Ninety-five dysregulated long noncoding RNAs and 123 messenger RNAs were identified, and quantitative real-time polymerase chain reaction was used to validate 6 filtered long noncoding RNAs. Gene Ontology and KEGG pathway analyses identified several remarkably biological processes and signaling pathways, including spliceosome, RNA transport, and ubiquitin-mediated proteolysis. The transcriptional factors MYC, GABPA, and E2F1 were found to play a central function in the long noncoding RNAs process, as indicated by the coexpression network. This study revealed the dysregulated long noncoding RNA profiles of mucosal gastric cancer. The results shed light on the biological function of long noncoding RNAs in gastric cancer pathogenesis. This provides useful information for exploring potential early screening biomarkers in gastric cancer.

151P - Gene expression profiling for a better understanding of gastric cancer: From the perspective of metabolic rearrangement

BackgroundMetabolic rearrangement has been shown to be an important characteristic for stomach adenocarcinomas. Here we aimed to improve our understanding of the tumorigenesis of gastric cancer by means of gene and protein expression profile analysis with a focus on metabolic genes and pathways. MethodsArray-based gene expression profiling of fresh frozen cancer tissues and adjacent normal tissues were obtained from 8 patients with gastric cancer at early stage by using Affymetrix oligonucleotide microarray. Assays targeted 179 unique genes related to cancer metabolism. The raw expression data were normalized using nSolver Analysis Software 3.0 and a dataset of gene expression ratios for GC vs. controls was generated. The p values were calculated using a paired t-test, and the threshold for up- and down-regulated genes was set at p value < 0.05. The protein expression of the dysregualted genes were detected by immunohistochemistry (IHC) in the formalin fixed paraffin embedded tissue blocks. The signal was quantified by the Allred score system which represented the estimated intensity and proportion of positive-staining cells. ResultsOur microarray results showed increased expression of 20 metabolic genes and decreased expression of 6 metabolic genes in all cases of gastric cancer at early stage. Besides of the undetected NOX4, the protein levels of all the others dysregualted genes, detected by IHC, showed consistently results. Half of all dysregulated genes (AKT2, EGLN3, G6PD, GLS, HIF1A, HK2, HRAS, MAP2K1, NTRK3, PGK1, PLCG1, RET and RPS6KB1) are implicated in Carbon Metabolism, a pivotal metabolic approach involving in nucleic acid biosynthesis. Five genes (ARNT, EGLN1, EGLN3, HIF1A and NOX4) are molecules implicated in hypoxia signaling. Besides, the upregulated HIF1A is a cancer metabolism driver, which means that HIF1A may induce the oncogenesis of gastric cancer. ConclusionsThe gastric mucosa in gastric cancer at early stage is characterized by dysregulated expression of a limited repertoire of metabolic genes. The nature of the corresponding metabolic rearrangement and pathways may help guide further investigations into its etiology. Legal entity responsible for the studyFudan University Shanghai Cancer Center. FundingNational Human Genetic Resources Sharing Service Platform (2005DKA21300), National Natural Science Foundation of China (81602078),. DisclosureAll authors have declared no conflicts of interest.

The correlation between uric acid and stages of malignancy among gastric cancer patient in Palembang, Indonesia

Gastric cancer is a malignant gastric mucosal cancer that often began on the side where the gastric layer is inflamed. Previous research has shown that high uric acid levels are associated independently with an increased risk of gastric cancer and it is suspected that there is a correlation between gastric cancer and elevated levels of uric acid levels but is still poorly known in detail. The aim of this study was to analyse the correlation between uric acid levels and stage of malignancy of gastric cancer patients in the oncology department of Mohammad Hoesin Hospital Palembang. This research was an analytic observational study by using a cross-sectional design to test the correlation between uric acid levels and stages of malignancy in gastric cancer. The results obtained was analyzed using Goodman and Kruskal’s Gamma correlation test. The Goodman and Kruskal’s gamma test results showed a strong correlation (p=0,033; r=0,746) between uric acid levels and which shows a significant correlation with 95% of confidence levels. Every increment in uric acid levels would be followed by an increase in stages of malignancy in gastric cancer.

Immunistochemical Analysis of the Expression of TGFβ, Galectin-1, Vimentin, and Thrombospondin in Gastric Cancer Associated with Systemic Undifferentiated Connective Tissue Dysplasia.

We performed immunohistochemical analysis of the expression of TGFβ, galectin-1, vimentin, and thrombospondin in the mucosa in gastric cancer of diffuse and intestinal type associated with systemic undifferentiated connective tissue dysplasia. In diffuse gastric cancer, both with and without association with connective tissue dysplasia, a higher level of expression of TGFβ, galectin-1, vimentin, and thrombospondin in the tumor was detected in comparison with the perifocal and tumor zones in intestinal gastric cancer, which may reflect the pathogenetic peculiarities of the two histotypes of gastric cancer. Intestinal type of gastric cancer associated with connective tissue dysplasia is characterized by a high level of expression of galectin-1 and vimentin in the perifocal zone and TGFβ in the tumor zone. The pattern of expression of the studied markers can reflect both the pathogenetic peculiarities of the two histotypes of gastric cancer and peculiar expression of some growth factors, cytoskeleton proteins, and matrix-cell proteins associated with undifferentiated connective tissue dysplasia which may contribute to epithelial-mesenchymal transition.

Periodic Methylation Patterns in the Background Mucosa of Gastric Cancer

Periodic Methylation Patterns in the Background Mucosa of Gastric Cancer

Risk of lymph node metastasis in undifferentiated-type mucosal gastric carcinoma

BackgroundEndoscopic resection (ER) has come to be recognized as a standard treatment for early gastric cancer (EGC). While its adoption is expanding, ER remains restricted to cases of EGC without lymph node metastasis for the treatment of local resection. On the other hand, histopathological analyses of surgically resected specimens of EGC have revealed the presence of lymph node (LN) metastasis in some cases of mucosal gastric cancer (MGC) and undifferentiated MGC (UD-MGC) is considered to have higher risk of nodal metastases than differentiated MGC (D-MGC). To evaluate the risk factors for LN metastasis in MGC, we investigated the characteristics of UD-MGC associated with LN metastasis.MethodsAmong all UD-MGC patients who underwent surgery as initial treatment, between January 2000 and March 2016, we reviewed the clinicopathological data, including the preoperative endoscopic findings and histopathological findings in the resected specimens, of the 11 UD-MGC patients who were identified as having lymph node metastasis. Furthermore, in comparison with cases without lymph node metastasis, we examined the possibility of expansion of the indication for local treatment.ResultsIn most of the cases of UD-MGC with LN metastasis, the lesions were relatively large (> 20 mm in diameter) and of the clearly depressed type with faded color and apparent border, and histopathology revealed a high percentage of cases with lymphatic invasion and a predominance of signet ring cell carcinomas. No cases with LN metastasis without depressed macroscopic type nor signet ring cell carcinoma component existed. A degree of invasion of lamina propria (LP) or muscularis mucosae (MM) had same relation to the risk of LN metastasis.ConclusionsIn this study, none of the cases of undifferentiated-type mucosal cancer (UD-MGC) with LN metastasis satisfied the current adoption criteria for ER. We suggested significant risk factors for LN metastasis in UD-MGC cases as depressed tumor type, presence of a signet ring cell carcinoma component, presence of lymphatic tumor invasion, and a large tumor size. More detailed analyses of the endoscopic and histopathological findings may allow further risk classification for LN metastasis in cases of UD-MGC.

Linked color imaging improves the endoscopic visibility of gastric mucosal cancers.

Background and study aims As a newly developed endoscopy technique, linked color imaging (LCI) provides very bright images with enhanced color tones. With the objective of improving the detection rate of gastric mucosal cancers, which are often difficult to detect, we examined the utility of LCI from the viewpoint of visibility. Patients and methods The current study used 100 consecutive gastric mucosal cancers ≤ 20 mm in diameter. For each lesion, we selected one endoscopic image acquired by white-light imaging (WLI), blue-laser imaging (BLI) -bright, and LCI modes. Four endoscopists interpreted the images; using a previously reported scale, we scored the visibility level on a scale of 1 – 4. Results The mean (± SD) visibility scores were 2.54 ± 1.10 for WLI, 3.02 ± 1.07 for BLI-bright, and 3.28 ± 0.97 for LCI. The score was significantly higher for BLI-bright compared with WLI ( P < .001) and again higher for LCI compared with BLI-bright ( P < .001). For the experts, the scores for BLI-bright and LCI were similar, but both were significantly higher than the score for WLI. For the trainees, there was no significant difference between the WLI and BLI-bright scores, but LCI score was significantly higher than those for WLI and BLI-bright scores. With regard to clinical characteristics, LCI particularly enhanced visibility of normochromic, flat and depressed lesions, which had the lowest visibility scores of all three modalities compared with those of the other lesions. Conclusion LCI increased visibility and may contribute to early detection of gastric mucosal cancers.

Clinical Implications of Microsatellite Instability in Early Gastric Cancer.

PurposeWe aimed to evaluate the clinical characteristics of microsatellite instability in early gastric cancer.Materials and MethodsThe microsatellite instability status of resected early gastric tumors was evaluated using two mononucleotide repeat markers (BAT25 and BAT26) and three dinucleotide repeat markers (D5S346, D2S123, and D17S250). Tumors with instability in two or more markers were defined as microsatellite instability-high (MSI-H) and others were classified as microsatellite stable (MSS).ResultsOverall, 1,156 tumors were included in the analysis, with 85 (7.4%) classified as MSI-H compared with MSS tumors. For MSI-H tumors, there was a significant correlation with the female sex, older age, tumor location in the lower gastric body, intestinal histology, lymphovascular invasion (LVI), and submucosal invasion (P<0.05). There was also a trend toward an association with lymph node (LN) metastasis (P=0.056). In mucosal gastric cancer, there was no significant difference in MSI status in tumors with LN metastasis or tumors with LVI. In submucosal gastric cancer, LVI was more frequently observed in MSI-H than in MSS tumors (38.9% vs. 25.0%, P=0.027), but there was no difference in the presence of LN metastases. The prognosis of MSI-H tumors was similar to that of MSS tumors (log-rank test, P=0.797, the hazard ratio for MSI-H was adjusted by age, sex, pT stage, and the number of metastatic LNs, 0.932; 95% confidence interval, 0.423–2.054; P=0.861).ConclusionsMSI status was not useful in predicting prognosis in early gastric cancer. However, the frequent presence of LVI in early MSI-H gastric cancer may help guide the appropriate treatment for patients, such as endoscopic treatment or limited LN surgical dissection.

More Frequent Follow-up CT Scans in Postsurgical Resection Patients Than in Postendoscopic Resection Patients of Early Gastric Cancers: Impracticality of CTs for Mucosal Cancer

The aim of this study was to compare the utility and timing of computed tomography (CT) in the detection of recurrent tumors between patients after surgical and endoscopic resections for early gastric cancer (EGC). A total of 670 patients after surgical (n = 535) and endoscopic (n = 135) resections for EGC between 2007 and 2009 were enrolled. The mean numbers of CT and endoscopy between both treatment groups were compared. The mean and cumulative dose length products of CT examinations were calculated. The modality that detected recurrence was compared between the two groups using the Pearson chi-square test. The mean interval of CT was significantly shorter and the mean number of CTs was significantly larger in the surgical resection group than in the endoscopic resection group. All 34 gastric recurrences were diagnosed by endoscopy. All seven extragastric recurrences occurred in patients treated for EGC with submucosal invasion. Six extragastric recurrences were detected by CT out of a total of 5417 CT scans. The average cumulative dose length product was significantly higher in the surgical group than in the endoscopic resection group (P = 0.004). Follow-up CTs were performed more frequently in patients after surgical resection than in patients after endoscopic resection of EGCs. However, CT scans were not effective in detecting recurrent tumors after either treatment methods, especially for patients treated for mucosal gastric cancer.