Genetic polymorphisms of XPD Arg156Arg and XPD Lys751Lys DNA
repair genes in patients whit Acute Myeloid Leukemia
Genetic polymorphisms of XPD Arg156Arg and XPD Lys751Lys DNA
repair genes in patients whit Acute Myeloid Leukemia
First author: Crauciuc GeorgeSecond author: Tripon
FlorinCoordinator: Conf. Dr.Claudia BnescuInternational Congress
for students, young physicians and pharmacists -
MarisiensisIntroductionLeukemia are clonal diseases which commonly
arise as a result of genetic damage deregulating blood cell
development or hematopoiesis.(1)
CommonUncommonViral infections:
HTLV IHIVEpstein BarrGenetic factors:
Chromosomal disorders (Down syndrome, aplasia marrow Fanconi,
syndrome Klinefelter) Molecular abdnormarlitiesFLT3, RAS, RUNX1,
NPM1 and XPD 156, 751Physico-chemical factors:
Ionizing radiationChemicals2XPDArg156Arg and XPDLys751Lys, is a
helicase involved in the nucleotide excision repair pathway, which
recognizes and repairs many structurally unrelated lesions(4).
It is plausible that small variations in the effiency of repair
in the normal population may facilitate cancer development in
exposed individuals.(2-3)ObjectiveThe aim of the study was to
estabilish some genetic relationship between AML and XPDArg156Arg
and XPDLys751Lys genes polymorphisms.Material98 patients and a
control group whit 157 healty persons.MethodsOur study population
consisted of blood from 98 patients with AML also 157 healty from
which we extracted DNA according to the protocol described by the
manufacturer (ZymoResearch DNAkit).
Genotypic analysis of the XPD156 C>A and XPD751 A>C
polymorphism was determined by the PCR-RFLP using specific
primers.Following PCR, 20l of PCR product was subjected to
restriction digestion using10 U of Pst I for XPD751 and Tfil l for
XPD 156 restriction enzyme(5) (Thermo Scientific Fast Digest).
The primers used to amplify the XPD gene were as follows:
for XPD 156 (exon 6): Forward primer: 5-TGG AGT GCT ATG GCA CGA
TCT CT-3Reverse: 5-CCA TGG GCA TCA AAT TCC TGG GA-3
for XPD 751 (exon 23):Forward primer: 5-ATC CTG TCC CTA CTG GCC
ATT CReverse primer: 5-TGT GGA CGT GAC AGT GAG AAC T-3
(7-8)Amplification was performed with an initial denaturation for
10 min at 95C, followed by 30 cycles of denaturation at 95C for 1
min, annealing at 60C for 1 min, extension at 72 C for 1min and a
final extension at 72C for 10 min.PCR protocolThe digested products
were resolved on 3% agarose gels (Sigma Chemical Co), stained with
ethidium bromide and analyzed under UV light.(6)Results62954058 The
mean age of all persons was 48.55 years, whit 18 years
deviation.
The success rate of genotyping was 90% in the first stage of
work and 100% in the second genotyping for the same DNA.
Results: Patients groupIn the AML group the gene XPD 156 was
found in the following variants: -homozygous normal (CC genotype)
at 30 people -heterozygous (CA genotype) at 51 and -homozygous
mutant (AA genotype) on 17.In the same group XPD 751 was found as:
-homozygous normal (AA genotype) at 33 people -heterozygous (AC
genotype) at 52 and -homozygous mutant (CC genotype) on 13.
Results: Control groupIn the control group the gene XPD 156 was
found in the following variants: -homozygous normal (CC genotype)
at 66 people -heterozygous (CA genotype) at 59 and -homozygous
mutant (AA genotype) on 32.In the same group XPD 751 was found as:
-homozygous normal (AA genotype) at 17 people -heterozygous (AC
genotype) at 51 and -homozygous mutant (CC genotype) on 30.
The marker used in the agarose gel has 100 pbXPD 751 C 480 pbA
352 pb 250 pbXPD 156 A 900 pbC 761 pb Statistical ResultsWild
TypeHeterozygousHomozygous Mutant Heterozygous and Homozygous
mutantXPD 156-p= 0.032OR: 2.876CI: 1.247-5.793p= 0.709OR: 1.169CI:
0.563-2.242p= 0.084OR: 1.644CI 0.963-2.804XPD 751-p= 0.128OR:
1.553CI: 0.895-2.692p= 0.529OR: 1.339CI: 0.594-3.02p= 0.148OR:
1.505CI: 0.89-2.543Conclusion and DiscussionsExist a correlation
between mutation in the XPD 156 gene and AML, whit statistical and
scientific significance.The distributions of theXPD156
andXPDLys751Gln genotypes were in accordance withHardy-Weinberg
equilibriumamong the controls (p= 0.176;p= 0.083, respectively) and
the AML cases.
Further studies with a large number of patients are needed as
well studies to demonstrate this genetic defects are important
factors in determining the desease and the response to chemotherapy
and outcome.DiscussionsWe continued to investigate the importance
of XPD mutations dividing individuals in another two groups: +50
years / -50 years.The statistical results remained the same, the
age is not related with the mutant genotype.
19 cases are FLT3 positive, No association was found between
FLT3 mutation and mutant genotypes studied.References Benhamou,S.
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