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
310P - A study on the prediction of recurrence site of endometrial cancer using various machine learning techniques
Presenter: Wonkyo Shin
Session: Poster Display
Resources:
Abstract
311P - Circulating cytokines in the differential diagnosis of endometrial cancer
Presenter: Tatyana Abakumova
Session: Poster Display
Resources:
Abstract
312P - Molecular and genetic features of squamous cell carcinoma of vulvar cancer depending on HPV status
Presenter: Visola Navruzova
Session: Poster Display
Resources:
Abstract
313P - Efficacy and safety of oral metronomic chemotherapy in recurrent refractory advanced gynaecological cancer: Experience from regional cancer center of eastern India
Presenter: Ranti Ghosh
Session: Poster Display
Resources:
Abstract
314P - Perioperative outcomes in advanced epithelial ovarian cancer treated with neoadjuvant bevacizumab and chemotherapy: Real-world experience from an Indian cancer centre
Presenter: Upasana Palo
Session: Poster Display
Resources:
Abstract
315P - Real-world experience of niraparib as maintenance therapy in newly diagnosed advanced ovarian cancer: A single-center retrospective study
Presenter: Wenxin Liu
Session: Poster Display
Resources:
Abstract
316P - First evidence of olaparib maintenance therapy in patients with newly diagnosed BRCA wild-type ovarian cancer: A real-world multicenter study
Presenter: Jing Li
Session: Poster Display
Resources:
Abstract
317P - Attitudes of Israeli gynecologists towards risk reduction salpingo-oophorectomy at hysterectomy for benign conditions and the use of hormonal therapy
Presenter: wisam Assaf
Session: Poster Display
Resources:
Abstract
319P - Survival prediction for ovarian cancer patients from Taiwan cancer registry data
Presenter: Tzu-Pin Lu
Session: Poster Display
Resources:
Abstract
320P - Treatment patterns and outcomes in Indian patients with advanced ovarian cancer: A single center experience
Presenter: Pushpendra Hirapara
Session: Poster Display
Resources:
Abstract