What is Tumor Mutation Burden?

A genomic biomarker that quantifies the frequency of somatic mutations in a patient’s tumor
TMB- high correlates with an aggressive tumor rapidly evolving with high incidence of somatic mutations per megabase of the tumor genome
This subsequently manifests as high neoantigen expression, helping the body’s immune system to recognize tumors

According to Globocan data from 2018, around 2.25 million people were affected by cancer
This number is known to grow by 1.15 million every year
Males are at 9.81% risk to develop cancer before the age of 75 and females at 9.42%

Common Cancers

High Tumor Mutation Burden has been detected across numerous tumor types and has been associated with improved response rate and prolonged progression-free survival for patients on immunotherapy
TMB expands the population of patients who can be considered candidates for immunotherapy beyond standard PD-L1 testing
Recently, FDA has approved Pembrolizumab for treating adult and pediatric patients with unresectable or metastatic solid tumors with high TMB (>10 Mut/Mb) that have progressed following previous therapy

Tumor Mutation Burden test by MedGenome provides quantification in terms of TMB score as well as accurate information on actionable mutations
A single test that analyzes all guideline-recommended genes in solid tumors, in addition to some of the rarely mutated genes in tumors
It identifies genomic alteration biomarkers across therapeutically / prognostically relevant (with FDA approved therapies) >400 genes with a median depth of coverage of 300X (LOD of 5% for SNVs and 10% for Indels)
The assay covers 1.3 Mb genomic region, across >400 genes relevant across major cancer types for the TMB estimation
MedGenome's TMB testing is internally validated extensively using clinical material i.e., FFPE tumor specimens from multiple cancer types such as lung, breast, colorectal, ovarian, brain tumors, hepatocellular carcinoma, pancreatic, renal cell carcinoma, head and neck, prostate, urothelial (Bladder cancer), Skin cancer and others, along with international reference standards and cell lines

Parameter	Result
Precision	100%
Specificity	100%
Sensitivity	99%
Repeatability	100%
Reproducibility	100%
LOD	5% for SNVs and 10% for Indels
Gene Fusions	minimum of 10 spanning read support
Gene Amplifications	>6 copies is considered positive for Gene amplifications

Note:

The scope of this NGS testing limits to TMB analysis (in DNA)
Cytosine deamination has significant impact on the score of TMB. The role of cytosine deamination artifacts (C>T) due to poor tissue fixation, age of the block and any other specimen processing related parameters, which are beyond the measure for quantification cannot be ruled out
Our threshold for tissue deamination is <10%
TMB Score is dependent on the choice of genes and the size of the panel
TMB testing is an evolving biomarker and there are no universal guidelines for the choice of genes and methodology used for the calculation of TMB
Different cancers and gene panels may have different cut-offs for Low, Intermediate and High. The current validation on this panel, is based on a limited subset of diverse cancer types from Indian cancer patients