Clinical Impact of Genomic and Genetic Data Disparity

Racial and ethnic minorities often experience cancer disparities in the United States with higher disease prevalence, shorter survival, and higher death rates with many cancer types. These disparities are proposed to reflect the complex interplay of non-biological (socioeconomic, environmental, behavioral) and biological factors (genetic and genomic features).  
Despite the recent efforts of the inclusion of minorities in genetic and genomic studies, data disparities between racial groups, both quantitatively and qualitatively, still exist and are clinically impactful. For example, tumor mutational burden (TMB) is an FDA-approved patient selection biomarker for immune checkpoint inhibitor (ICI) therapy. Last year, our group reported the over-estimation of TMB in patients of African ancestry due to the common clinical practice of tumor-only sequencing without patient-paired germline data and the ineffective germline variant removal resulting from the under-representation of minority groups in public variant databases. This year, we were the first to report the lower sequencing data quality of ancestrally African patients in The Cancer Genome Atlas (TCGA), one of the largest and most widely used cancer sequencing projects, which resulted in lower qualities of both germline variants and somatic mutations in Black patients.  
The clinical impact of the observed data disparity needs to be studied to overcome this major barrier in solving cancer genomics disparities in ancestrally African patients.  

Learning Objectives:

1. Demonstrate the type of therapy for which the tumor mutational burdens (TMB) status is used as a biomarker, per FDA.

2. Discuss the data quality disparity between patients with European and African ancestries in the TCGA.

3. Explain the strategies to overcome inflated TMB estimate in patients of African ancestry.