At CeGaT, the TMB score can be evaluated based on different sequencing approaches. The best choice for a specific project depends on the underlaying scientific question and availability of patient material. Typically, the TMB score is assessed through whole-exome sequencing of the tumor tissue, as well as the corresponding normal tissue (e.g. blood sample). By comparing the variants detected in both samples, we can discriminate between tumor specific (somatic) mutations, and mutations present in every tissue of the patient.
However, recent studies have shown that the TMB score can also be effectively estimated if only a panel of genes gets sequenced, provided the sequencing panel covers a genomic region of at least 1,5 Mb (Buchhalter 2018). Thus, for many cases, it is not only sufficient but even more expedient to analyze a selected panel of genes. Therefore, we make use of our CeGaT somatic tumor panel which comprises more than 700 selected, cancer-related genes.
Clinical samples are very precious material and availability is often limited. A comparison of tumor and normal tissue might not always be possible. To meet this challenge, CeGaT uses the solution provided by Illumina, in which TMB score is evaluated based on tumor tissue analysis only: TruSight Oncology 500 (TSO500) comprises the next-generation sequencing based analysis of 523 cancer-relevant genes and their standardized bioinformatic assessment. No normal tissue is required.
For the most comprehensive results, CeGaT’s customers always receive information about the tumor’s microsatellite instability (MSI) in addition to TMB analysis – regardless of whether it is based on TSO500, whole-exome sequencing, or CeGaT somatic tumor panel sequencing. Besides TMB, MSI is another important biomarker for the patient’s response to immunotherapy.
Contact us in order to find out which TMB product is the best choice for your study.
Combine your TMB analysis with the following services offered by CeGaT Research and Pharma Solutions:
- Detection and sequencing of certain immune subpopulations (e.g. CD4+, CD8+, PD-1+ T cells)
- Detection of (neo)antigen-specific T cells
- Microbiome analysis
- T cell receptor (TCR) sequencing
- Human leukocyte antigen (HLA) analysis
- Transcriptome sequencing