Abstract P6-02-09: Racial/Ethnic Groups Have Different Rates of Pathogenic Variants in Common Cancer Genes
Authors: Beitsch Peter , Wernecke Chloe , Patel Rakesh , Rosen Barry , Compagnoni Gia , Grady Ian , Brown Eric , Gold Lindsay , Whitworth Pat , Smith Linda Ann , Wirga Mariusz , Reitherman Richard , Cai Steven , Nguyen Toan , Traina Valerie , Holmes Dennis , Baron Paul , Krautheim Brittany , Peled Anne , Taylor Walt , Bontempo Kelly , Bentley Brenna , Ortega Krista , Ahmadi Pouyan 
Published: March 2023

Background: Racial/ethnic disparities have been well-documented in access to cancer screening and treatment, as well as treatment outcomes. Less is known regarding the yield of genetic pathogenic variants (PVs) in non-white populations.

Methods: Patient data was obtained from the Informed Genetics Annotated Patient Registry (iGAP), an IRB-approved multi-center longitudinal, observational study, in which 2148 patients self-declared race/ethnicity and underwent germline genetic testing at any lab. Analyses were limited to 24 cancer susceptibility genes (ATM, BARD1, BRCA1, BRCA2, BRIP1, CDH1, CHEK2, NBN, PALB2, PTEN, STK11, TP53, APC, BMPR1A, CDK4, EPCAM, MLH1, MSH2, MSH6, MUTYH, PMS2, RAD51C, RAD51D, SMAD4), 21 of which have clinical management guidelines from the NCCN (excluding NBN, BARD1, CDK4).1 Descriptive statistics were used to assess and compare data from these populations and germline genetic testing results.

Results: The Registry included 2148 patients, 1662 (77.37%) with a personal history and 1536 (71.51%) with a family history of cancer. The patients were 74.39% White, 6.33% Hispanic, 5.59% African/Black, 5.03% Asian, 1.63% Other, 1.35% Ashkenazi, and 5.68% Unknown. The overall germline PV rate in the cohort was 0.1089 PVs/patient tested, with 234 PVs detected in 227 patients. The PV rate among racial/ethnic groups were as follows: White 170/1598 (0.1064), Asian 8/108 (0.0741), Hispanic 27/136 (0.1985), African/Black 11/120 (0.0917), Ashkenazi 6/29 (0.2069). In patients self-reporting as Hispanic, the PV rate was similar to PV rate in those self-reporting as Ashkenazi, and significantly higher (p=0.00027) than PV rate in those of other self-reported race/ethnicity. Gene level PV rates are shown in Table 1.

Conclusions: Those who reported being Hispanic had an increased overall PV rate. This could be due to the greater representation of Hispanics from New Mexico who may have Ashkenazi ethnicity. Further studies are needed to understand whether these differences are a result of disparate access to testing, true population differences, lack of data in non-White populations skewing variant classification or other factors.

Table 1. Gene PV Rates by Racial/Ethnic Category.

Citation Format: Peter Beitsch, Chloe Wernecke, Rakesh Patel, Barry Rosen, Gia Compagnoni, Ian Grady, Eric Brown, Lindsay Gold, Pat Whitworth, Linda Ann Smith, Mariusz Wirga, Richard Reitherman, Steven Cai, Toan Nguyen, Valerie Traina, Dennis Holmes, Paul Baron, Brittany Krautheim, Anne Peled, Walt Taylor, Kelly Bontempo, Brenna Bentley, Krista Ortega, Pouyan Ahmadi. Racial/Ethnic Groups Have Different Rates of Pathogenic Variants in Common Cancer Genes [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-02-09.