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
362P - Efficacy and safety of MCLA-129, an anti-EGFR/c-MET bispecific antibody, in head and neck squamous cell cancer (HNSCC)
Presenter: Irene Braña
Session: Poster Display
Resources:
Abstract
363P - Effect of financial distress and mental well-being of patients with early vs advanced oral cancer on informal caregiver's quality of life: A prospective real-world data from public health sector hospital
Presenter: Abhinav Thaduri
Session: Poster Display
Resources:
Abstract
364P - Artificial intelligence provides more accurately neck lymph nodes auto-segmentation in radiotherapy
Presenter: chiencheh Chen
Session: Poster Display
Resources:
Abstract
365P - Radiotherapy treatment outcomes and treatment compliance of nasopharyngeal cancer patients in Sabah: A retrospective analysis
Presenter: Anbarasan Anbazagan
Session: Poster Display
Resources:
Abstract
366P - Pre-treatment oral fungal microbiome and nasopharyngeal carcinoma prognosis: A population-based cohort study in southern China
Presenter: Yufeng Chen
Session: Poster Display
Resources:
Abstract
367P - Prevalence and association of sarcopenia with mortality in patients with head and neck cancer: A meta-analysis
Presenter: Claire Lim
Session: Poster Display
Resources:
Abstract
368P - Distinct gene expression profiling explored using nanostring tumor signalling 360 panel with validations in different clinical stages of oral submucous fibrosis patients: A first Indian study
Presenter: Yasasve Madhavan
Session: Poster Display
Resources:
Abstract
370P - Low-dose nivolumab with induction chemotherapy for inoperable HNSCC in 111 patients: Response rates, survival, and implications for LMICs
Presenter: Josh Thomas Georgy
Session: Poster Display
Resources:
Abstract
371P - The role of FDG-PET/CT in the assessment of response to radiation therapy in head and neck cancers: A systematic review and meta-analysis
Presenter: Felix Wijovi
Session: Poster Display
Resources:
Abstract
372P - Effectiveness of HAN-MI-RADS (head and neck molecular imaging-reporting and data system) criterion in head and neck squamous cell carcinoma post concurrent chemoradiotherapy
Presenter: Manoj Gupta
Session: Poster Display
Resources:
Abstract