Abstract 60P
Background
Using liquid-based next generation sequencing (NGS) to detect circulating tumor DNA (ctDNA) and understanding genetic profiling has become more accessible recently. However, there is still limited prospective data in Asian breast cancer patients. This study is using Guardant360 to identify the genetic landscape of patients with recurrent breast cancer (BC) and de novo stage IV metastatic BC in an Asian population and to demonstrate genetic profile changes at disease progression.
Methods
Patients with either recurrent BC or de novo stage IV BC underwent both tissue-based NGS and liquid-based NGS before systemic therapy, and had liquid-based NGS done at PD. All patients were recruited from MacKay Memorial hospital from Jan 2020 to Dec 2021. The study was suspended in Jan 2022 due to restructuring of the sponsor’s organisation. Oncomine Comprehensive Assay was used for tissue based NGS, and Guardant360 was used for liquid based NGS.
Results
There were 44 patients (age range: 37-90 years old) recruited in the study, with 55 liquid samples (44 baseline and 11 PD samples), and 46 primary tissue samples or metastatic tissue samples in total. All the 46 tissue samples and all the 55 liquid samples were successfully sequenced. Out of the 44 liquid samples prior systemic therapy, ctDNA were detected in 84% (n=37) of the samples. Among of these 37 ctDNA positive samples, 64% of them have targetable alterations detected, including PIK3CA (31.8%, n=14), BRCA2 (20.5%, n=9), BRCA1 (9.1%, n=4), ERBB2 (4.6%, n=2), ESR1 (4.6%, n=2), FGFR2 amplification (4.6%, n=2), AKT1 (2.3%, n=1), and FGFR1 amplification (2.3%, n=1). In the study, we observed that higher percentage BRCA2/BCRA1 mutation was detected by liquid biopsy. A total of 31 patients underwent liquid and tissue NGS. We observed a high concordance in ESR1 alteration with 100%. Of the 12 patients with PIK3CA mutation detected in liquid and/or tissue, 8 were detected in both tissue and liquid, 2 detected in tissue alone and 2 detected in liquid alone.
Conclusions
Liquid-based NGS can be applied in clinical practice to identified clinically important mutations in Asian patients with recurrent breast cancer (BC) and de novo stage IV metastatic BC.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
P-S. Yang.
Funding
Yonglin Foundation, Taipei, Taiwan.
Disclosure
All authors have declared no conflicts of interest.
Resources from the same session
5P - Clinicopathologic features and genomic profiling of occult breast cancer
Presenter: Liansha Tang
Session: Poster Display
Resources:
Abstract
6P - Tumor cell-released autophagosomes (TRAPs) promote lung metastasis through inducing PD-L1 high expression of pulmonary vascular endothelial cells (PVECs) in breast cancer
Presenter: Xuru Wang
Session: Poster Display
Resources:
Abstract
7P - Tumor cell-released autophagosomes (TRAPs) promote breast cancer lung metastasis by modulating neutrophil extracellular traps formation
Presenter: Xiaohe Zhou
Session: Poster Display
Resources:
Abstract
9P - Clinicopathological features and prognosis of mucinous breast cancer: A retrospective analysis of 358 patients in Vietnam
Presenter: Hoai Hoang
Session: Poster Display
Resources:
Abstract
10P - Comparison of 28-gene and 70-gene panel in risk-prediction of Chinese women with early-stage HR-positive and HER2-negative breast cancer
Presenter: Lei Lei
Session: Poster Display
Resources:
Abstract
11P - Multimodal analysis of methylation and fragmentomic profiles in plasma cell-free DNA for differentiation of benign and malignant breast tumors
Presenter: Hanh Nguyen
Session: Poster Display
Resources:
Abstract
12P - Plasma cell-free mRNA profiles enable early detection of breast cancer
Presenter: Chi Nguyen
Session: Poster Display
Resources:
Abstract
13P - Relationship of distress and quality of life with gut microbiome composition in newly diagnosed breast cancer patients: A prospective, observational study
Presenter: Chi-Chan Lee
Session: Poster Display
Resources:
Abstract
14P - Classification of molecular subtypes of breast cancer in whole-slide histopathological images using a novel deep learning algorithm
Presenter: Hyung Suk Kim
Session: Poster Display
Resources:
Abstract
15P - The regulation of pregnenolone in breast cancer
Presenter: Hyeon-Gu Kang
Session: Poster Display
Resources:
Abstract