Non-homologous End-joining Genotype, mRNA Expression, and DNA Repair Capacity in Childhood Acute Lymphocytic Leukemia

Background/Aim: The capacity for non-homologous end-joining (NHEJ) repair plays a pivotal role in maintaining genome stability and in carcinogenesis. However, there is little literature on the involvement of NHEJ-related genes in childhood acute lymphocytic leukemia (ALL). Our study aimed to elucidate the impact of polymorphisms of X-ray repair crosscomplementing group 4 (XRCC4) (rs6869366, rs2075685, rs2075686, rs28360071, rs3734091, rs28360317, rs1805377), XRCC5 (rs828907, rs11685387, rs9288518), XRCC6 (rs5751129, rs2267437, rs132770, rs132774), XRCC7 rs7003908, and DNA ligase IV (LIG4) rs1805388, on the odds of childhood ALL. Materials and Methods: Genotypes NHEJrelated genes of 266 cases and 266 controls were determined, and the genotype-phenotype correlation was investigated by examining mRNA transcript expression and the capacity for overall and precise NHEJ repair. Results: The variant genotypes of XRCC4 rs3734091, rs28360071, XRCC5 rs828907, and XRCC6 rs5751129 were significantly associated with increased odds of childhood ALL. Further analysis based on susceptibility genotypes showed no significant differences in mRNA transcript expression levels among childhood ALL cases with various putative high-risk genotypes, except XRCC6 rs5751129. Moreover, the overall NHEJ repair capacity was similar among carriers of different XRCC4, XRCC5, and XRCC6 genotypes. However, it is worth noting that individuals carrying the variant C allele at XRCC6 rs5751129 exhibited lower precise NHEJ repair capacity compared to those with the wild-type T allele. Conclusion: Our study identified significant associations between XRCC4 rs3734091, rs28360071, XRCC5 rs828907, and XRCC6 rs5751129 genotypes and childhood ALL. Notably, lower transcriptional expression and reduced precise NHEJ repair capacity were observed in patients carrying the C allele of XRCC6 rs5751129. Further investigations are required to gain deeper insights into childhood ALL development.