• Journal of Digestive Cancer Research
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• v.3 no.1
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• pp.11-16
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• 2015

The discovery of HER2, a biomarker in advanced gastric cancer, and successful clinical trial using trastuzumab that targets this biomarker signaled a revolutionary turning point in treatment of metastatic gastric cancer. Many studies about targeted agents for gastric cancer have been attempted. Among them, ramicirumab, a monoclonal antibody that targets vascular endothelial growth factor receptor-2 (VEGFR-2), and apatinib, a tyrosine kinase inhibitor (TKI) that targets VEGFR2, have shown to improve the survival rates in advanced gastric cancer patients, for whom previous therapies had failed; hence, they are expected to be accepted as one of the standard therapies for advanced gastric cancer.

• Journal of Gastric Cancer
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• v.24 no.1
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• pp.4-28
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• 2024

Liquid biopsy, a minimally invasive procedure that causes minimal pain and complication risks to patients, has been extensively studied for cancer diagnosis and treatment. Moreover, it facilitates comprehensive quantification and serial assessment of the whole-body tumor burden. Several biosources obtained through liquid biopsy have been studied as important biomarkers for establishing early diagnosis, monitoring minimal residual disease, and predicting the prognosis and response to treatment in patients with cancer. Although the clinical application of liquid biopsy in gastric cancer is not as robust as that in other cancers, biomarker studies using liquid biopsy are being actively conducted in patients with gastric cancer. Herein, we aimed to review the role of various biosources that can be obtained from patients with gastric cancer through liquid biopsies, such as blood, saliva, gastric juice, urine, stool, peritoneal lavage fluid, and ascites, by dividing them into cellular and acellular components. In addition, we reviewed previous studies on the diagnostic, prognostic, and predictive biomarkers for gastric cancer using liquid biopsy and discussed the limitations of liquid biopsy and the challenges to overcome these limitations in patients with gastric cancer.

• Journal of Gastric Cancer
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• v.22 no.4
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• pp.273-305
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• 2022

Gastric cancer (GC) is one of the most common lethal malignant neoplasms worldwide, with limited treatment options for both locally advanced and/or metastatic conditions, resulting in a dismal prognosis. Although the widely used morphological classifications may be helpful for endoscopic or surgical treatment choices, they are still insufficient to guide precise and/or personalized therapy for individual patients. Recent advances in genomic technology and high-throughput analysis may improve the understanding of molecular pathways associated with GC pathogenesis and aid in the classification of GC at the molecular level. Advances in next-generation sequencing have enabled the identification of several genetic alterations through single experiments. Thus, understanding the driver alterations involved in gastric carcinogenesis has become increasingly important because it can aid in the discovery of potential biomarkers and therapeutic targets. In this article, we review the molecular classifications of GC, focusing on The Cancer Genome Atlas (TCGA) classification. We further describe the currently available biomarker-targeted therapies and potential biomarker-guided therapies. This review will help clinicians by providing an inclusive understanding of the molecular pathology of GC and may assist in selecting the best treatment approaches for patients with GC.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.4
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• pp.1667-1670
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• 2014

Background: Calprotectin in feces seems to be a more sensitive marker for gastrointestinal (GI) cancers than fecal occult blood, but its specificity may be too low for screening average risk populations. This study aims at evaluating the diagnostic value of fecal calprotectin as a screening biomarker for GI malignancies. Materials and Methods: In a case-control study, 100 patients with GI malignancies (50 patients with colorectal cancer and 50 patients with gastric cancer) and 50 controls were recruited in Tabriz Imam Reza and Sina hospitals during a 24-month period. One to two weeks after the last endoscopy/colonoscopy, fecal specimens were collected by the patients and examined by ELISA method for quantitative measurement of calprotectin content. The results were compared between the three groups. Results: The mean fecal calprotectin level was $109.1{\pm}105.3$ (2.3-454.3, median:74), $241.1{\pm}205.2$ (3.4-610.0, median:19.3) and $45.9{\pm}55.1{\mu}g/g$ (1.3-257.1, median:19.3) in gastric cancer, colorectal cancer and control group, respectively, the differences being significant (p<0.001) and remaining after adjustment for age. The optimal cut-off point for fecal calprotectin was ${\geq}75.8{\mu}g/g$ for distinguishing colorectal cancer from normal cases (sensitivity and specificity of 80% and 84%, respectively). This value was ${\geq}41.9{\mu}g/g$ for distinguishing gastric cancer from normal cases (sensitivity and specificity of 62%). Conclusions: Our results revealed that fecal calprotectin might be a useful and non-invasive biomarker for distinguishing colorectal cancer from non-malignant GI conditions. However, due to low sensitivity and specificity, this biomarker may not help physicians distinguishing gastric cancer cases from healthy subjects.

• Journal of Gastric Cancer
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• v.23 no.3
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• pp.410-427
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• 2023

Recent advances in artificial intelligence (AI) have provided novel tools for rapid and precise pathologic diagnosis. The introduction of digital pathology has enabled the acquisition of scanned slide images that are essential for the application of AI. The application of AI for improved pathologic diagnosis includes the error-free detection of potentially negligible lesions, such as a minute focus of metastatic tumor cells in lymph nodes, the accurate diagnosis of potentially controversial histologic findings, such as very well-differentiated carcinomas mimicking normal epithelial tissues, and the pathological subtyping of the cancers. Additionally, the utilization of AI algorithms enables the precise decision of the score of immunohistochemical markers for targeted therapies, such as human epidermal growth factor receptor 2 and programmed death-ligand 1. Studies have revealed that AI assistance can reduce the discordance of interpretation between pathologists and more accurately predict clinical outcomes. Several approaches have been employed to develop novel biomarkers from histologic images using AI. Moreover, AI-assisted analysis of the cancer microenvironment showed that the distribution of tumor-infiltrating lymphocytes was related to the response to the immune checkpoint inhibitor therapy, emphasizing its value as a biomarker. As numerous studies have demonstrated the significance of AI-assisted interpretation and biomarker development, the AI-based approach will advance diagnostic pathology.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.11
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• pp.5563-5568
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• 2012

Based on our previous report on gastric cancer which documented ATP4A and ATP4B mRNA down-regulation in gastric tumors relative to normal gastric tissues, we hypothesized that epigenetic mechanisms could be responsible. ATP4A and ATP4B mRNA expression in gastric cancer cell lines AGS, SNU638 and NUGC-3 was examined using reverse transcriptase PCR (RT-PCR). AGS cells were treated with TSA or 5'-AzaDC and methylation specific PCR (MSP) and bisulfite sequencing PCR (BSP) analysis were performed. MSP analysis was on DNA from paraffin embedded tissues sections and plasma. Expression analysis revealed downregulation of ATP4A and ATP4B genes in gastric cancer cell lines relative to normal gastric tissue, while treatment with 5'-AzaDC re-activated expression of both. Search for CpG islands in their putative promoter regions did not indicate CpG islands (CGI) but only further downstream in the bodies of the genes. Methylation specific PCR (MSP) in the exon1 of the ATP4B gene and exon7 in ATP4A indicated methylation in all the gastric cancer cell lines tested. MSP analysis in tumor tissue samples revealed methylation in the majority of tumor samples, 15/19, for ATP4B and 8/8 for ATP4A. There was concordance between ATP4B and ATP4A down-regulation and methylation status in the tumour samples tested. ATP4B methylation was detectable in cell free DNA from gastric cancer patient's plasma samples. Thus ATP4A and ATP4B down-regulation involves DNA methylation and methylated ATP4B DNA in plasma is a potential biomarker for gastric cancer.

• Genomics & Informatics
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• v.13 no.3
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• pp.70-75
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• 2015

MicroRNAs (miRNAs) have been demonstrated to play an important role in carcinogenesis. Previous studies revealed that miRNAs are present in human plasma in a remarkably stable form that is protected from endogenous RNase activity. In this study, we measured the plasma expression levels of three miRNAs (miR-21, miR-27a, and miR-155) to investigate the usefulness of miRNAs for gastric cancer detection. We initially examined plasma miRNA expression levels in a screening cohort consisting of 15 patients with gastric cancer and 15 healthy controls from Korean population, using TaqMan quantitative real-time polymerase chain reaction. We observed that the expression level of miR-27a was significantly higher in patients with gastric cancer than in healthy controls, whereas the miR-21 and miR-155a expression levels were not significantly higher in the patients with gastric cancer. Therefore, we further validated the miR-27a expression level in 73 paired gastric cancer tissues and in a validation plasma cohort from 35 patients with gastric cancer and 35 healthy controls. In both the gastric cancer tissues and the validation plasma cohort, the miR-27a expression levels were significantly higher in patients with gastric cancer. Receiver-operator characteristic (ROC) analysis of the validation cohort, revealed an area under the ROC curve value of 0.70 with 75% sensitivity and 56% specificity in discriminating gastric cancer. Thus, the miR-27a expression level in plasma could be a useful biomarker for the diagnosis and/or prognosis of gastric cancer.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.5
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• pp.2719-2722
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• 2016

Circulatory miR-133a is a marker shared by several types of cancer. In this study we evaluated the feasibility of using miR-133a levels in gastric juice to screen for gastric cancer. A total of 204 samples of gastric juice and mucosa from gastric cancer, atrophic gastritis, gastric ulcer, superficial gastritis and healthy cases were collected by gastroscopy. The results showed that miR-133a levels in gastric juice and carcinoma tissues of patients with gastric cancer were significantly downregulated and positively correlated. Moreover, miR-133a in gastric juice has high operability, high reliability, high sensitivity, high specificity and relative stability, fit for clinical diagnosis of gastric cancer.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.19
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• pp.8367-8370
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• 2014

The relationship between caveolin-1 (Cav-1) and clinicopathological characteristics of gastric cancer is controversial, although Cav-1 plays an important role in tumor metastasis. To evaluate the clinicopathological and prognostic value of expression in patients with gastric cancer, a meta-analysis was performed to investigate the impact on clinicopathological parameters and prognosis in gastric cancer cases. Studies assessing these parameters for Cav-1 in gastric cancer were identified up to June 2014. Finally, a total of six studies met the inclusion criteria. Our combined results showed that Cav-1 expression was significantly associated with the Lauren classification (pooled OR=0.603, 95% CI: 0.381-0.953, P=0.030). Furthermore, we found that Cav-1 expression predicted a better overall survival in gastric cancer patients (pooled OR=0.590, 95% CI: 0.360-0.970, P=0.038, fixed-effect). In conclusion, the overall data of the present meta analysis showed that Cav-1 expression was not correlated with clinicopathological features except for the Lauren classification. Simultaneously, Cav-1 overexpression predicted a better overall survival in gastric cancer. Cav-1 expression in tumors is a candidate positive prognostic biomarker for gastric cancer patients.

• YAKHAK HOEJI
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• v.56 no.6
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• pp.358-363
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• 2012

Nemo-like kinase (NLK), an evolutionarily conserved serine/threonine protein kinase, plays an important role in wide variety of developmental events. NLK phosphorylates T-cell factor/lymphoid enhancer factor (TCF/LEF) transcriptional complex and suppresses wnt signaling pathway through inhibition of ${\beta}$-catenin/TCF complex interaction. However, the function of NLK in gastric carcinogenesis has not been investigated. In the present study, we have examined whether the NLK gene is involved in the development and/or progression of gastric cancers. NLK expression was analyzed by immunohistochemical staining in 153 advanced gastric cancer specimens. Immunhistochemical analysis showed increased expression of NLK in 91 (59.5%) out of 153 gastric cancer specimens. Statistically, there was no significant relationship between altered expression of NLK protein and clinicopathological parameters, including tumor differentiation, location, lymph node metastasis. We identified that mRNA and protein expression of NLK was significantly up-regulated in human gastric cancer tissues compare to corresponding normal gastric tissues. In addition, we found that human gastric cancer cell lines exhibited relatively high expression of NLK, as compared with normal gastric cells. The results of this study suggest that aberrant regulation of NLK may contribute to the development or progression of gastric cancers and serve as a potential biomarker for advanced gastric cancer patients.