May 15, 2023

Precise and reliable genomic profiling is key for identifying new therapeutic targets, making treatment decisions, and monitoring disease progression. Uncovering critical genetic information about tumor biology, predictive biomarkers, and immune responses can aid in the selection of appropriate patients and optimize study outcomes.

The TruSight Oncology 500 (TSO500) assay is a next-generation sequencing (NGS) pan-cancer panel that allows for comprehensive profiling of tumor samples and the simultaneous identification of pertinent cell-free DNA, and genomic DNA and RNA variants implicated in various tumor types1. Specifically, 523 different cancer-related genes from DNA and 55 from RNA, plus immuno-oncology genomic biomarkers, such as microsatellite instability (MSI) and tumor mutational burden (TMB), can be identified in blood or formalin-fixed paraffin-embedded (FFPE) tissue specimens1.

With TSO500, labs have the flexibility to choose between manual or automated workflows. However, automated workflows achieve high-quality results with higher throughput, enhancing lab efficiency and saving labor costs. TSO500 assays improve biomarker discovery and provide insightful details using only a minimal amount of sample, thus saving precious samples.

How can the TSO500 panel improve the development of cancer therapies?

The development of immunotherapies requires rigorous assessment of immuno-oncology biomarkers, including TMB and MSI, as well as other genetic markers such as RNA fusions, single nucleotide variant (SNV), insertions/deletions (indels), and copy number variation, all of which can be determined via TSO500 2,3.

MSI status has traditionally been evaluated via PCR and immunohistochemistry techniques. While such methods provide qualitative insight into MSI-stable or MSI-high status, the TSO500 assay evaluates 130 specific homopolymer MSI marker sites, producing a quantitative score for MSI status1. Additionally, determining consistent TMB values at low mutation levels can pose challenges when using smaller panels. TSO500 overcomes this obstacle by seamlessly integrating genomic content with advanced algorithms, resulting in precise TMB estimates highly concordant with whole-exome studies.

Consolidating multiple biomarker assays into one comprehensive NGS assay requires less sample, provides a quicker turnaround time, and significantly increases the chances of finding positive biomarkers1.

Improve TSO500 testing with CellCarta’s support

When conducting large-scale genomic studies, it is important to have access to required facilities and a reliable team with expertise in the latest technologies. Our global footprint and logistics expertise ensure that your samples reach our experts and undergo appropriate processing in a timely fashion. Large-scale genomic studies can become quite costly, which is why we offer the NovaSeq platform in conjunction with TSO500 to allow for analysis of 16-192 samples per run, thus providing scalable throughput for dynamic study sizes4.

At CellCarta, we offer our broad range of services and biomarker expertise to provide solutions for your study needs and to support our partners in propelling precision medicine. Contact our team to speak to an expert about your clinical trials.


About the author:

author photo

Sara Diels (PhD) is an assay development scientist at the Genomics Services unit within CellCarta. She led the implementation of the TSO500 High-Throughput and ctDNA assay at the Antwerp site. Her background is in molecular biology, and she has experience in the field of disease genetics where different -omics technologies are used to examine multifactorial inheritance. At CellCarta, Sara has expanded her expertise with the development and validation of PCR- and NGS-based assays.


  1. TruSight Oncology 500 Assay | For pan-cancer biomarkers in DNA and RNA.
  2. Pestinger, V. et al. Use of an Integrated Pan-Cancer Oncology Enrichment Next-Generation Sequencing Assay to Measure Tumour Mutational Burden and Detect Clinically Actionable Variants. Mol Diagn Ther 24, 339–349 (2020).
  3. Wei, B. et al. Evaluation of the TruSight Oncology 500 Assay for Routine Clinical Testing of Tumor Mutational Burden and Clinical Utility for Predicting Response to Pembrolizumab. Journal of Molecular Diagnostics 24, 600–608 (2022).
  4. NovaSeq 6000 System.