Genetic ancestry, differential gene expression, and survival in pediatric B-cell acute lymphoblastic leukemia.

BACKGROUND: Black children have lower incidence yet worse survival than White and Latinx children with B-cell acute lymphoblastic leukemia (B-ALL). It is unclear how reported race/ethnicity (RRE) is associated with death in B-ALL after accounting for differentially expressed genes associated with genetic ancestry. METHODS: Using Phase 1 and 2 NCI TARGET B-ALL cases (N = 273; RRE-Black = 21, RRE-White = 162, RRE-Latinx = 69, RRE-Other = 9, RRE-Unknown = 12), we estimated proportions of African (AFR), European (EUR), and Amerindian (AMR) genetic ancestry. We estimated hazard ratios (HR) and 95% confidence intervals (95% CI) between ancestry and death while adjusting for RRE and clinical measures. We identified genes associated with genetic ancestry and adjusted for them in RRE and death associations. RESULTS: Genetic ancestry varied within RRE (RRE-Black, AFR proportion: Mean: 78.5%, Range: 38.2%-93.6%; RRE-White, EUR proportion: Mean: 94%, Range: 1.6%-99.9%; RRE-Latinx, AMR proportion: Mean: 52.0%, Range: 1.2%-98.7%). We identified 10, 1, and 6 differentially expressed genes (padjusted  <0.05) associated with AFR, AMR, and EUR ancestry proportion, respectively. We found AMR and AFR ancestry were statistically significantly associated with death (AMR each 10% HR: 1.05, 95% CI: 1.03-1.17, AFR each 10% increase HR: 1.03, 95% CI:1.01-1.19). RRE differences in the risk of death were larger in magnitude upon adjustment for genes associated with genetic ancestry for RRE-Black, but not RRE-Latinx children (RRE-Black HR: 3.35, 95% CI: 1.31, 8.53; RRE-Latinx HR: 1.47, 0.88-2.45). CONCLUSIONS: Our work highlights B-ALL survival differences by RRE after adjusting for ancestry differentially expressed genes suggesting other factors impacting survival are important.

Survival disparities for childhood cancers exist when defined by race/ethnicity and sex.

BACKGROUND: There are documented racial/ethnic and sex differences in pediatric cancer survival; however, it is unknown whether pediatric cancer survival disparities exist when race/ethnicity and sex are considered jointly. METHODS: Using SEER data (2000-2017), we estimated survival differences by race/ethnicity within sexes and by sex within race/ethnicity (White, Black, Hispanic, and Asian/Pacific Islander [API]) for 17 cancers in children aged (0-19 years). Kaplan-Meier curves (Log-Rank p-values) were assessed. Cox regression was used to estimate hazards ratios (HRs) and 95 % confidence intervals (95 % CIs) between race/ethnicity/sex and cancer. RESULTS: We included 51,759 cases (53.6 % male, 51.9 % White). There were statistically significant differences in 18-year survival by race/ethnicity-sex for 12/17 cancers. Within sexes, minorities had an increased risk of death compared to Whites for various cancers including acute lymphoblastic leukemia (ALL) (females: HispanicHR: 1.78, 95 % CI: 1.52, 2.10; BlackHR: 1.70, 95 % CI: 1.29, 2.24; APIHR: 1.42, 95 % CI: 1.07-1.89; males ALL: HispanicHR: 1.58, 95 % CI: 1.39,1.79; BlackHR: 1.57, 95 % CI: 1.26,1,95; API-HR: 1.39, 95 % CI: 1.11, 1.75) and astrocytoma (females: HispanicHR: 1.49, 95 % CI: 1.19, 1.85; BlackHR: 1.67, 95 % CI: 1.29, 2.17; API-HR: 1.51, 95 % CI: 1.05, 2.15; males: HispanicHR:1.27, 95 % CI: 1.04, 1.56; BlackHR: 1.69, 95 % CI: 1.32, 2.17; API-HR: 1.92, 95 % CI: 1.43, 2.58). Sex differences in survival within racial/ethnic groups were observed for White (ALL, osteosarcoma), Hispanic (medulloblastoma), and API (Primitive Neuro-Ectodermal Tumor [PNET]) children. CONCLUSIONS: There are disparities in survival by both race/ethnicity and sex highlighting the societal and biologic influences these features have on survival in children with cancer.