The genes involved in DNA repair system play a crucial role in the protection against
mutations .It has been hypothesized that functional deficiencies in highly conserved
DNA repair processes resulting from polymorphic variation may increase genetic
susceptibility to breast cancer. There are multiple pathways to repair the different
types of DNA damage and maintain genomic integrity among them is the nucleotide
excision repair (NER) and the base excision repair (BER) pathways. Aim & methods:
The aim of the present study was to examine the relation between the DNA repair
gene polymorphisms and breast cancer (BC) risk in Egyptian females and to analyze
their relation to clinico-pathological parameters of BC and also to investigate the
synergistic effect of both genes on BC susceptibility . Both XPD and XRCC1
polymorphisms were characterized in 100 BC Egyptian females and 100 healthy
women who had no history of any malignancy by amplification refractory mutation
system -polymerase chain reaction (PCR) (ARMS) method and PCR with confronting
two-pair primers(PCR–CTPP) , using DNA from peripheral blood in a case control
study. RESULTS: our results revealed that the frequencies of AA genotype of XPD
codon 312 polymorphism were significantly higher in the breast cancer study patients
than in the normal individuals(p≤0.003), and did not observe any association
between the XRCC1 Arg399Gln polymorphism and risk of developing breast cancer
Also, no association between both XPD Asp312Asn and XRCC1 A399G
polymorphisms and the clinical characteristics of disease Finally ,the combination
of AA(XPD)+AG(XRCC1) were significantly associated with breast cancer risk. In
conclusion, the present results suggest that, XPD gene is an important candidate
gene for susceptibility to breast cancer. Also, gene–gene interaction between
XPD(AA)+XRCC1(AG) polymorphism may be associated with increased risk of
breast cancer in Egyptian women.