The role of racial genetic admixture with endometrial cancer outcomes: An NRG Oncology/Gynecologic Oncology Group study.

Rocconi RP, Lankes HA, Brady WE, Goodfellow PJ, Ramirez NC, Alvarez RD, Creasman W, Fernández JR
Gynecol Oncol 140 264-9 02/01/2016


PURPOSE: Racial genetic admixture (RGA), a measure to account for ancestral genetic background that correlates with individual's racial classification, could provide insights on causation of racial disparity in endometrial cancer (EC). Our objective is to evaluate the association of RGA with EC outcomes.

METHODS: EC patients enrolled onto the GOG-210 protocol were eligible. A randomized subcohort stratified by stage and self-reported race/ethnicity of black or white was used. Genotyping was performed using custom-selected Ancestry Informative Markers to calculate individual admixture estimates of African and European ancestral background.

RESULTS: A total of 149 patients were evaluated (self-reported race: 70 black & 79 white). Mean RGA for African ancestry for self-reported black patients was 0.65 (range 0.04-0.86); while mean RGA for European ancestry for self-reported white patients was 0.77 (range 0.12-0.88). Progression-free survival (PFS) analysis using proportional hazards models stratified by stage and race revealed that each 0.10 increase in African ancestry was associated with worse PFS with hazard ratio (HR) of 1.11 (95% CI 0.90-1.37). Each 0.10 increase in European RGA was associated with improved PFS with HR of 0.86 (95% CI 0.69-1.07). Using tertiles of African RGA showed increasing risk of progression of death with increasing African RGA (with 0-5% as reference), HR (95% CIs) for top two tertiles are: 6%-66%: 1.38 (0.64, 2.97), and 67%-86%: 2.27 (0.74, 6.95).

CONCLUSION: RGA demonstrated a trend with PFS in self-reported black and white patients with EC. Patients with increased levels of African ancestry showed a trend towards worse survival after stratifying by stage/race.

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