St. Jude Children's Research Hospital-led study links inherited variations in a few genes to a substantially increased risk of acute lymphoblastic leukemia and helps to explain ethnic differences in the cancer's incidence
Humans have between 20,000 and 25,000 genes that carry instructions for assembling the proteins that do the work of cells. Work led by St. Jude Children's Research Hospital found that children who inherit certain variations in four particular genes are at much higher risk of developing acute lymphoblastic leukemia (ALL).
The study also showed that Hispanic patients were more likely than patients of European or African ancestry to inherit high-risk versions of two of these genes. ALL rates are known to be higher among Hispanic children than those of European or African ancestry, this discovery points to at least one reason for that difference.
Each person's genome includes two copies of each gene, one from each parent. Thus, individuals could inherit up to eight high-risk versions of the four genes tied to an increased ALL risk. In this study, researchers found that having more than five copies of the risk genes resulted in a nine-fold greater risk of developing ALL in childhood than inheriting no more than one copy.
The report appears online March 19 in the Journal of the National Cancer Institute.
The findings stem from one of the largest multi-ethnic studies of genetic variation and ALL susceptibility ever conducted. The work included 2,450 pediatric ALL patients and 10,977 individuals from diverse racial and ethnic backgrounds without the disease.