A genome-wide association study identifies an African-specific locus on chromosome 21q22.12 associated with Burkitt lymphoma risk and survival

Abstract

Burkitt lymphoma (BL) is a B-cell malignancy that disproportionately affects children in sub-Saharan Africa. We performed a genome-wide association study (GWAS) in a combined set of 800 childhood cases and 3865 controls in East Africa, controlling for age, sex, country, population-specific principal components, and a genetic relationship matrix. This analysis identified a BLprotective region within chromosome 21q22.12 tagged by the rs111457485-T allele (odds ratio [OR] = 0.57; p = 5.7 × 10−9 ). The results were robust in standard meta-analysis (OR = 0.57, p < 1.6 × 10−8 ), sensitivity analyses (removing genomic outliers and related individuals), and after adjustment for Epstein-Barr virus (EBV) status. Genomic analyses revealed long-range (over ~700 kb) chromatin interactions between the chr21q22.12 locus and the RUNX1-P1 promoter region. The African-specific rs2242780-C allele (r 2 = 0.69 with the rs111457485-T allele in the study controls) showed increased enhancer activity in in-vitro Luciferase reporter assays (p = 4.5 × 10−10), nominating it as the likely functional variant for the BL-associated loci. In addition to the association with reduced BL risk in GWAS (OR = 0.62, p = 2.24 × 10−8 ), the rs2242780-C allele was also associated with better survival in patients with abdominal-only BL in exploratory analyses (hazard ratio = 0.39, p = 0.038, 106 patients, 59 deaths). Our GWAS uncovered novel BL-protective loci near RUNX1, offering insights into the genetic etiology of BL in African children.