Cancer Epidemiology Biomarkers & Prevention: Multilocus association of genetic variants in MLL, CREBBP, EP300, and TOP2A with childhood acute lymphoblastic leukemia in Hispanics from Texas

Background: Hispanic children have both a higher incidence and a poorer outcome in acute lymphoblastic leukemia (ALL). Moreover, a higher incidence for therapy-related acute myeloid leukemia with 11q23 translocations after treatment with topoisomerase II (topo II) inhibitors has been observed in Hispanic children with ALL. We sought to determine the potential role of genetic variants within the topoisomerase IIα gene (TOP2A), within the mixed lineage leukemia gene (MLL) and two of its translocation partners, cyclin AMP response element-binding protein gene (CREBBP) and E1A binding protein gene (EP300) in the increased sensitivity of Hispanic children with ALL to topo II inhibitors.

Methods: Fifty-two tagged single nucleotide polymorphisms (SNP) covering the four genes were genotyped in 241 samples (66 children with ALL and 175 age-matched controls) of self-identified Hispanic origin.

Results: Two SNPs within MLL (rs525549 and rs6589664) and three SNPs within EP300 (rs5758222, rs7286979, and rs20551) were significantly associated with ALL (P = 0.001-0.04). A significant gene-dosage effect for increasing numbers of potential high-risk genotypes (OR = 16.66; P = 2 × 10(-5)) and a major haplotype significantly associated with ALL (OR = 5.68; P = 2 × 10(-6)) were found. Replication in a sample of 137 affected White children and 239 controls showed that only rs6589664 (MLL) was significantly associated in this ethnic group.

Conclusions: Our findings indicate that the association between ALL and common genetic variants within MLL and EP300 is population specific.

Impact: Replication of our findings in independent Hispanic populations is warranted to elucidate the role of these variants in ALL susceptibility and define their importance in the ethnic-specific differences in ALL risk.