Abstract 175P
Background
Advanced gastric adenocarcinoma with both lymph node and peritoneal metastasis has notoriously poor prognosis. However, molecular mechanism of the metastatic process and potential therapeutic targets remain unknown, hence limiting the development of new therapies.
Methods
We recruited 13 treatment-naïve patients who had gastric adenocarcinoma with concurrent lymph node and peritoneal metastasis. DNA and RNA were extracted from tumor biopsy samples collected from the stomach, lymph node and peritoneum, together with 2 mL of peripheral blood for each patient. Whole exome sequencing (WES) and transcriptome sequencing were performed to generate a comprehensive genomic dataset of our cohort.
Results
Analysis of WES data showed that TP53 and CDH1 were the most frequently mutated genes in both the primary and metastatic tumors. All patients had low tumor mutational burden, but 31% (n=4) showed high level of chromosomal instability (CIN). By constructing tumor phylogenetic trees for each patient, we found evidence supporting two distinct processes of peritoneal dissemination that involved either lymphatic system (n=5) or direct seeding into the peritoneal cavity (n=4). In the RNA sequencing analysis, epithelial-mesenchymal transition (EMT) pathway was found the most significantly altered and segregated the patients into the EMT-high group (n=10) that upregated genes in the EMT pathway, and the non-EMT-high group (n=3).
Conclusions
Multi-omics profiling in this study revealed mutational signature and altered signaling pathways in lymph node and peritoneal metastasis. The results could help identify distinct molecular subtypes among patients, laying foundation for the development of molecular-guided therapeutic strategies.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
Medical Genetics Institute, Ho Chi Minh city, Vietna.
Funding
Gene Solutions JSC, Ho Chi Minh city, Vietnam.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
442P - Negative impact on bone homeostasis in postmenopausal women with non-metastatic breast cancer during cytotoxic chemotherapy
Presenter: Yadav Nisha
Session: Poster Display
Resources:
Abstract
443P - Efficacy of vitamin D supplementation in overall survival of cancer patients: Systematic review and meta-analysis
Presenter: Visakha Irawan
Session: Poster Display
Resources:
Abstract
444P - Commencing a nurse led symptom and urgent review clinic (SURC) in a Victorian regional cancer centre
Presenter: Sue Bartlett
Session: Poster Display
Resources:
Abstract
445P - Self-reported symptom burden, quality of life and unmet need of symptom management in nasopharyngeal cancer survivors: A cross-sectional survey
Presenter: Jerry Ching
Session: Poster Display
Resources:
Abstract
446P - A single center experience of anamorelin in patients with non-small cell lung cancer
Presenter: Takanori Ito
Session: Poster Display
Resources:
Abstract
447P - Quality of life in patients with EGFR-mutated lung cancer receiving gefitinib vs gefitinib plus pemetrexed and carboplatin chemotherapy
Presenter: Nandini Menon
Session: Poster Display
Resources:
Abstract
448P - Association of clinicopathological characteristics and pro-inflammatory markers with reduced relative dose intensity in breast cancer chemotherapy
Presenter: Susanna Hutajulu
Session: Poster Display
Resources:
Abstract
449P - Psychometric validation of the MD Anderson symptom inventory head&neck module: Chinese version in nasopharyngeal cancer survivors
Presenter: Victor Tam
Session: Poster Display
Resources:
Abstract
450P - Retrospective study of anamorelin therapy for unresectable or recurrent pancreatic cancer with cancer cachexia
Presenter: Mao Okada
Session: Poster Display
Resources:
Abstract
451P - The real-world efficacy and safety of anamorelin hydrochloride for Japanese unresectable non-small cell lung cancer patients with cachexia
Presenter: Daisuke Arai
Session: Poster Display
Resources:
Abstract