Abstract 500P
Background
Biomarker testing has gradually become standard of care in precision oncology to help physicians select optimal treatment for patients. Compared to single-gene or small gene panel testing, comprehensive genomic profiling (CGP) has emerged as a more time- and tissue- efficient method. However, the clinical utilization of CGP has not been evaluated in developing countries like Vietnam.
Methods
We collected 190 FFPE samples from patients diagnosed with 10 common types of cancer. DNA extracted from FFPE was subjected to next-generation sequencing (NGS) using a panel of 473 cancer-relevant genes (K-4Care, Gene Solutions, Vietnam). All actionable mutations including single nucleotide variants, small insertion/deletions, gene amplification and fusion, were reported to select FDA-approved targeted therapies. Complex biomarkers for immunotherapy including microsatellite instability (MSI) and tumor mutational burden (TMB) were analyzed for all patients.
Results
At least one actionable mutation was identified in 38.9% (74/190) of the patients, with the highest rate in thyroid (68.4%), breast (57.1%) and lung (50.0%) cancers. MSI-high was found mostly in patients with colorectal cancer (16.9%) and ovarian cancer (9.1%). We also compared this NGS-based MSI analysis with the gold standard PCR method using the MSI Analysis System (Promega) and found the high concordance rate of 97%. For TMB, a value higher than 10 mutations/Mb was defined as TMB-high for lung cancer and its prevalence was 38% (14/36). The proportion of lung cancer patients having TMB-high/PD-L1-positive and TMB-high/PD-L1-negative were 21.7% (5/23) and 21.7% (5/23) respectively.
Conclusions
Our assay provides comprehensive and reliable genomic information that fulfills all guideline-based biomarker testing for both targeted therapy and immunotherapy.
Clinical trial identification
Editorial acknowledgement
Legal entity responsible for the study
The authors.
Funding
Gene Solutions JSC, Ho Chi Minh city, Vietnam.
Disclosure
All authors have declared no conflicts of interest.