Purpose: Asparaginase (ASNase) is a standard and critical component in the therapy of childhood acute lymphoblastic leukemia (ALL), but it is also associated with several toxicities.
Experimental design: We recently reported the results of an association study between ASNase pathway genes and event-free survival (EFS) in childhood patients with ALL. The same polymorphisms were interrogated here in relation to allergies, pancreatitis, and thrombotic events following treatment with
E. coli ASNase.
Results: Among patients of the discovery group, allergies, and pancreatitis were more frequent in individuals who are homozygous for the triple-repeat allele (
3R) of the asparagine synthetase (
ASNS) gene, resulting in remarkably higher risk of these toxicities associated with
3R3R genotype [OR for allergies, 14.6; 95% confidence interval (CI), 3.6–58.7;
P < 0.0005 and OR for pancreatitis, 8.6; 95% CI, 2.0–37.3;
P = 0.01]. In contrast, the
ASNS haplotype
*1 harboring double-repeat (
2R) allele had protective effect against these adverse reactions (
P ≤ 0.01). The same haplotype was previously reported to confer reduction in EFS. The risk effect of
3R3R genotype was not replicated in the validation cohort, whereas the protective effect of haplotype
*1 against allergies was maintained (
P ≤ 0.002). Analysis with additional polymorphisms in
ASNS locus in lymphoblastoid cell lines showed that haplotype
*1 is diversified in several subtypes of which one was associated with reduced
in vitro sensitivity to ASNase (
rs10486009,
P = 0.01) possibly explaining an association seen in clinical setting.
Conclusions: This finding might have implication for treatment individualization in ALL and other cancers using asparagine depletion strategies.
Clin Cancer Res; 21(2); 329–34. ©2014 AACR.
See related commentary by Avramis, p. 230