Tumor Mutational Burden: Guidelines for derivation and robustness of measurement

Explore our Tumor Mutational Burden (TMB) calculation methodology

Tumor mutational burden (TMB) is defined as the number of somatic mutations per Mb of the genome and is used to represent accumulation of somatic mutations over the life of the tumor. Recent evidence has shown that high TMB scores are associated with improved response to immune therapies across multiple indications. However, the derivation of this score is not well characterized, nor is this score universally performed across laboratories.

In this poster, we describe our methodology for calculating TMB, which considers an estimation of true germline mutations and the identification of regions within a capture panel that most reliably contribute to robust TMB scoring.

In addition, we introduce a method to determine the effect on TMB scores when in silico determination of germline variants is used to derive somatic calls when matching normal samples are not available. Defining the robustness of this score across and criteria for its derivation will help better position defining analytical range and future utility across indications and NGS panels.

Natalie Mola
Wendell Jones, Ph.D., Principal Bioinformaticist and Scientific Advisor
Victor Weigman, Ph.D., Director, Translational Genomics

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