Association between genetic polymorphism of xrcc7 and susceptibility to acute lymphocytic leukemia

Farnoush Farokhian,1 Mani ramzi,2 Zahra beyzaei,3,*

1. Islamic Azad university of Zarghan, Shiraz, Iran
2. Hematology Research Center, Shiraz University of Medical Sciences, Shiraz, Iran
3. Islamic Azad university of Zarghan, Shiraz, Iran



acute lymphoblastic leukemia (all) is the most common malignant tumor in the children that comprises over 80% of all the acute leukemia. the etiology and pathogenesis of all are unclear up to now. previous studies make a plausible hypothesis that crucial sequential events involving specific chromosomal translocations or fusion genes as the first hits to initiate all and further genetic or epigenetic events such as gene deletions or mutations as the second hits to cooperate to the outbreak of all. one of the most important initiating events is thought to result from the misrepair of double-strand dna breaks (dsb) during non-homologous end-joining (nhej). xrcc7 (mim: 600889) is one of the most important dna double-strand break (dsbs) repair gene, involved in non-homologous end joining (nhej) pathway. moreover, it is reported that dna repair function could be modified by genetic polymorphisms. it could cause genetic instability and even carcinogenesis if dna repair capacity is of deficiency. functional polymorphism in xrcc7 (g6721t) may be risk factors for all. therefore aim of the present study is investigated the association between the genetic polymorphism of xrcc7 and risk of all.


The present case–control study was performed a total of 100 all patients, and 200 normal people, as a control group. control group had no history of any cancer with pe. genotypes of subjects were determined using a pcr/rflp based method. a chi-square test was performed for xrcc7 polymorphisms to determine if the sample groups demonstrated hardy–weinberg equilibrium. the association between the study polymorphisms and susceptibility to all was examined using the odds ratios (or) and 95 % of confidence intervals (cis). statistical analysis was performed using spss statistical software package (version 16) for windows (spss inc., chicago, il, usa).


The genotypic frequencies for the polymorphism among controls were in hardy–weinberg equilibrium (χ2 = 6.048, df = 1, p = 0.048). the prevalence of 6721g allele in our control group (0.4697) was similar to the caucasian populations. in this study base on classification of acute lymphocytic leukemia was founded significant associations between b cell group compared t cell group (or = 0.33, 95% ci = 0.1 – 0.9; or = 3.4, 95% ci = 0.88 – 19.4, respectively). also, a significant association between gt genotype (xrcc7) in patients group compared to control group (or = 1.8, 95% ci = 1.09 – 3.06) were observed.


Although there were some deficiencies in this study, the comprehensive research results showed that xrcc7 6721g>t polymorphism could increase the risk of childhood all, which was to be significant to some extent. because this not only can deeply enhance our knowledge of the childhood all pathogenesis, which will offer potential targets for therapeutic intervention, but also assess the risk of childhood all in order to take effective measures to protect vulnerable populations meanwhile, it is essential to study the correlation between all and gene polymorphism in iranian children. more researches are needed to investigate the relationship between dna repair genes polymorphisms and childhood all.


Xrcc7, single nucleotide polymorphism, acute lymphocytic leukemia, childhood