IKZF1 Gene in Childhood B-cell Precursor Acute Lymphoblastic Leukemia: Interplay between Genetic Susceptibility and Somatic Abnormalities

SNPs in IKZF1 are associated with inherited susceptibility to B-cell precursor acute lymphoblastic leukemia (BCP-ALL). Besides, somatic copy number abnormalities (CNA) in genes related to lymphopoiesis (e.g., IKZF1, CDKN2A/B, BTG1) impact patient's outcome. Therefore, this study aimed to investigate an association between germline susceptibility and CNAs in BCP-ALL. The IKZF1 SNPs (rs11978267 and rs4132601) were genotyped in 276 cases and 467 controls. Bone marrow samples were used to determine the presence of somatic abnormalities. The IKZF1 transcript levels were quantified and associated with the SNPs and CNAs. Categorical variables were compared by ² test. ORs were estimated with unconditional logistic regression with 95% confidence interval (CI). The variant allele of IKZF1 rs4132601 conferred increased risk of BCP-ALL (OR, 2.09; 95% CI, 1.16–3.74). Individuals with either rs11978267 or rs4132601 had an increased risk for harboring IKZF1 deletion (OR, 2.80; 95% CI, 1.25–6.23 and OR, 2.88; 95% CI, 1.24–6.69, respectively). Increased risks were observed for individuals harboring both IKZF1 and BTG1 deletions (OR, 4.90; 95% CI, 1.65–14.55, rs11978267 and OR, 5.80; 95% CI, 1.94–17.41, rs4132601). Germline genetic variation increases the risk for childhood ALL in general, but also acts as a susceptibility factor bound for risk of specific somatic alterations. These findings provide new insight into the development of childhood ALL regarding causal variants and the biological basis of the risk association, offering the opportunity for future tailored research. Cancer Prev Res; 10(12); 738–44. ©2017 AACR.

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