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. 2022 May;18(5):e805-e813.
doi: 10.1200/OP.22.00090.

Disparities in Cancer Genetic Testing and Variants of Uncertain Significance in the Hispanic Population of South Texas

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Disparities in Cancer Genetic Testing and Variants of Uncertain Significance in the Hispanic Population of South Texas

Stephanie Soewito et al. JCO Oncol Pract. 2022 May.

Abstract

Purpose: Racial and ethnic disparities have included a lack of access to both genetic testing and research, resulting in poor understanding of the genomic architecture in under-represented populations. The South Texas population is primarily of Hispanic background and has been largely devoid of genetic services. We extended access to this underserved population and uncovered genetic variants previously not observed, emphasizing the need to continually improve both genomic databases and clarification of variant significance to provide meaningful patient counseling.

Methods: This study consisted of a retrospective cohort review of patients seen through a cancer genetics education and service program across 24 counties in South Texas. In total, 1,595 individuals were identified as appropriate for cancer genetic counseling and 1,377 completed genetic testing.

Results: Eighty percent of those receiving genetic counseling self-identified as Hispanic, 16% as non-Hispanic White (NHW), 3% as African American, and 1% as other race/ethnicity. Of reported variants, 18.8% were pathogenic and 13.7% were reported as a variant of uncertain significance (VUS). VUS was reported in 17.2% of the Hispanic individuals compared with 9% NHW (P = .005).

Conclusion: Individuals of Hispanic ethnicity were significantly more likely to harbor a VUS compared with NHW. The extended reach into our regional communities revealed a gap in the ability to accurately interpret genomic variation with implications for advising patients on screening, prevention, and management strategies. A higher percentage of VUS also emphasizes the challenge of continued follow-up amid existing barriers that led to disparities in access. As understanding of the variants develops, hopefully gaps in knowledge of the genomic landscape will be lessened with increased clarity to provide accurate cancer risk assessment and recommendations for implementing prevention initiatives.

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Conflict of interest statement

Shawn GessayEmployment: PreventionGeneticsStock and Other Ownership Interests: Exact Sciences Lindsey MetteEmployment: InVitaeStock and Other Ownership Interests: InVitae Pamela M. OttoHonoraria: Seno MedicalConsulting or Advisory Role: Seno MedicalResearch Funding: Seno Medical, Guerbet Chethan RamamurthyConsulting or Advisory Role: Seattle GeneticsSpeakers' Bureau: Gilead Sciences Virginia G. KaklamaniHonoraria: Genentech, Novartis, Pfizer, Genomic Health, Puma Biotechnology, AstraZeneca, Seattle Genetics, Daichi, Gilead SciencesConsulting or Advisory Role: Amgen, Eisai, Puma Biotechnology, Celldex, AstraZeneca, Athenex, bioTheranosticsSpeakers' Bureau: Genentech, Novartis, Genomic Health, Puma Biotechnology, Pfizer, AstraZeneca/Daiichi SankyoResearch Funding: Eisai Gail E. TomlinsonConsulting or Advisory Role: Cardinal HealthNo other potential conflicts of interest were reported.

Figures

FIG 1.
FIG 1.
Map of Texas with locations of major sites for activities. Bilingual health educators were based in Laredo (Webb County), McAllen/Edinburg region (Hidalgo County), and Harlingen (Cameron County). Genetic counselors were based in San Antonio and worked with individuals from throughout our catchment area primarily by telehealth methods, as described, but also provided periodic education and outreach counseling sessions to cities indicated and other sites along the western Texas border.
FIG 2.
FIG 2.
Distribution of pathogenic mutations and variants of uncertain significance. (A) Comparison of VUS percentages between the non-Hispanic White 9% (shown in blue) and Hispanic 17.2% (shown in red) populations. (B) Number of VUS (blue) and pathogenic variants (red) identified in BRCA1/2 genes which were the genes with most observed variants. BRCA1 (n = 11 VUS; n = 82 PV) and BRCA2 (n = 21 VUS; n = 33 PV). (C) Number of VUS (blue) and pathogenic variants (red) identified in genes other than BRCA1/2. PV, pathogenic variant; VUS, variant of uncertain significance.
FIG 3.
FIG 3.
Reclassification of VUS. Remained as VUS were those identified initially, not changed of status by commercial company used and remained as VUS in the ClinVar and/or available scientific literature. Variants listed as not available are variants identified in our population, but not reported in ClinVar or other sources. VUS, variant of uncertain significance.

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