Transcriptomic Signatures in Gastric Adenocarcinoma

Study Overview
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Brief Summary
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Gastric Adenocarcinoma (GAC) accounting for the major percentage of all stomach malignancies is associated with a poor overall survival of 25-30% despite the advancement in treatment strategies. Several factors associated with tumor microenvironment (TME) are thought to play an important role in tumorigenesis and acquired chemoresistance to therapies that are not otherwise addressed by the comprehensive molecular classification of GAC given by TCGA and ACRG. In the present study investigators intend to do transcriptome profiling of GAC tumor tissue and adjacent normal tissue to investigate differentially expressed genes between the two in relation to TME which might help in identification of gene signatures that are clinically relevant with survival outcome in Gastric Adenocarcinoma.

Detailed Description
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This study on Gastric adenocarcinoma is retrospective as well as prospective that will be conducted at SGPGIMS, Lucknow, India. Patients undergoing gastric resection at the department of surgical gastroenterology who are diagnosed with GAC based on the endoscopic biopsy in the department of pathology will be recruited for the study. For the retrospective part of study, cases will be selected based on histological findings retrieved from hospital information system and patient records. For sample collection, surgically resected fresh specimens will be collected in RNAlater and stored at -80⁰C. Archived formalin fixed paraffin embedded (FFPE) tissue blocks for retrospective cases will be retrieved and reviewed histopathologically. After a confirmed diagnosis of GAC, tissues will be processed to obtain tumor and normal tissue for experimental part. RNA from the tumor and normal area will be extracted from FFPE blocks and fresh tissue specimens. Whole transcriptomic next generation sequencing will be performed after successful quality check, library preparation and amplification. The gene expression data obtained from sequencing will be bioinformatically analyzed to elucidate differential gene expression between tumor and adjacent normal tissue in relation to TME. The significantly differentially expressed genes between the tumor and normal areas will be annotated and identified using bioinformatic packages for gene annotation. Using statistical analysis, the differentially expressed genes will be correlated with the patient's clinical features and outcome to identify TME genes with significant prognostic value.

Official Title
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Exploring the Transcriptomic Signatures and Their Relevance in Gastric Adenocarcinoma

Conditions
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Gastric Adenocarcinoma

Intervention / Treatment
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* Diagnostic Test: Observational study


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Patients with origin of tumor in distal part of stomach Patients who underwent Total or partial Gastrectomy after Biopsy examination Availability of follow up in Radiotherapy or Gastro department Availability of FFPE gastrectomy specimen tissue of selected cases in Histopathology Exclusion Criteria: Patients with origin of tumor in proximal part of stomach Patients with only biopsy available Patients whose follow-up is not available Unavailability of FFPE tissue blocks

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Patients with Gastric Adenocarcinoma<br>Patients with origin of tumor in distal part of stomach who underwent total or partial gastrectomy after biopsy examination with availability of follow-up and archived FFPE tissue will be considered for this study. | Diagnostic Test: Observational study<br>* Exploration of transcriptomic signatures related to tumor microenvironment having a significant role in prognosis of gastric adenocarcinoma patients<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Transcriptome profiling of Gastric adenocarcinoma | To obtain gene expression data of cancerous and normal tissue through RNA - sequencing | Range of 6 months to 5 years of patient recruitment | 
| Differential gene expression analysis in Gastric adenocarcinoma | To determine differentially expressed gene between tumor and normal tissue through bioinformatic analysis of gene expression data | Range of 6 months to 5 years of patient recruitment | 
| Influence of tumor microenvironment on gene expression profile of gastric adenocarcinoma | To identify tumor microenvironment related genes and their functional annotation using bioinformatic packages | Range of 6 months to 5 years of patient recruitment | 
| Correlation of tumor microenvironment related genes with patient's clinical features | To correlate differentially expressed tumor microenvironment related gene with outcome in patients to identify genes significantly related with overall survival | Range of 6 months to 5 years of patient recruitment | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Patient risk stratification based on correlation between gene expression and overall survival | To stratify patients based on gene signatures related to overall survival in gastric adenocarcinoma patients | Range of 6 months to 5 years of patient recruitment | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Gastric cancer, Tumor microenvironment, Transcriptomics, Differential gene expression