Base excision repair (BER) systems have important role for repairing oxidative DNA damage, and known to influence the carcinogenesis and the response to anti-cancer treatments. Although few studies have shown that several DNA repair genes are associated with an increased risk of leukemia, the clinical significance of BER polymorphisms in acute myeloid leukemia (AML) patients remains unclassified. The aim of this study was to evaluate the impact of polymorphisms in genes encoding four main proteins of BER system: OGG1 Ser326Cys, MUTYH Gln324His, APE1 Asp148Glu, and XRCC1 Arg399Gln, and on the risk of AML.
Between December 1991 and May 2013, 99 patients (male/female 55/44, median age 58 years, range 15-86 years) diagnosed as AML and 192 healthy controls were included in this study. Cytogenetic subgroups were classified as good, intermediate, and adverse risk according to NCCN guidelines. Genomic DNA was isolated from peripheral blood using the DNA extraction kit. Genotyping was determined by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technique. Genotype and allele frequencies were compared between patients group and control group by using χ2-test. Probability values <0.05 were considered statistically significant. All patients and healthy controls received written information about the study. This study was approved by the Institutional Research Board of Gunma University Hospital.
The APE1 Asp/Asp genotype increases the risk of AML (OR 2.30, 95% CI 1.41-3.77, p<0.001), whereas APE1 Glu/Glu genotype reduces the risk of AML (OR 0.34, 95% CI 0.14-0.80, p<0.05). In contrast, there were no significant differences in the genotype frequencies OGG1 Ser326Cys, MUTYH Gln324His, and XRCC1 Arg399Gln between AML patients and control group. Next we compared the frequency of cytogenetic abnormalities according to BER polymorphism. The AML patients with OGG1 Ser/Ser genotype increased the frequencies of (15;17) type (p<0.05) and good risk group. Moreover, the AML patients with MUTYH His/His genotype increased the frequencies of complex type (p<0.02) and reduced the frequencies of t(8;21) type.
According to our data, BER gene polymorphisms may affect the carcinogenesis and the cytogenetic risk of AML.
No relevant conflicts of interest to declare.
Asterisk with author names denotes non-ASH members.