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
397P - Comparison between Y-site co-infusion versus standard dexamethasone for preventing hypersensitivity reactions from oxaliplatin administration: A randomized controlled trial
Presenter: jarearnjit Phavirunsiri
Session: Poster Display
Resources:
Abstract
398P - Evaluation of the effectiveness of denosumab therapy giant cell tumor of the pelvis
Presenter: Abbos Nurjabov
Session: Poster Display
Resources:
Abstract
399P - Long-term outcomes of patients with gastric cancer who received the best supportive care without any anticancer treatment
Presenter: Yohei Arihara
Session: Poster Display
Resources:
Abstract
401TiP - Oral opioid vs intravenous patient-controlled analgesia (PCA) with hydromorphone bolus-only or continuous infusion to maintain analgesia for severe cancer pain: A randomized phase III trial
Presenter: Cheng Huang
Session: Poster Display
Resources:
Abstract
407P - K-TrackTM: A streamlined personalized assay to detect molecular residual disease in solid tumors
Presenter: Nam Vo
Session: Poster Display
Resources:
Abstract
408P - Increased EGFR and MET expression and corresponding tumor microenvironment (TME) change in hepatocellular carcinoma (HCC) tissues after sorafenib (Sora) treatment
Presenter: Chia Jui Yen
Session: Poster Display
Resources:
Abstract
410P - Systematic evaluation of cell-free DNA fragmentation patterns for cancer diagnosis and enhanced cancer detection through integration of multiple fragmentations
Presenter: Xiangy-Yu Meng
Session: Poster Display
Resources:
Abstract
412P - Multiplex digital spatial profiling (DSP) of protein reveals distinct immune and molecular phenotypes in hepatocellular carcinoma
Presenter: Chia Jui Yen
Session: Poster Display
Resources:
Abstract
413P - Clinical utility of advanced features provided by circulating tumor DNA-based comprehensive genomic profiling
Presenter: Young-gon Kim
Session: Poster Display
Resources:
Abstract
414P - Landscape of ERBB2 mutations in advanced cancers (AC) using circulating tumor DNA (ctDNA) next-generation sequencing (NGS) in Asia and Middle East (AME)
Presenter: Byoung Chul Cho
Session: Poster Display
Resources:
Abstract