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Single Nucleotide Polymorphism in
Xenobiotic and Estrogen Metabolizing Genes
and Breast Cancer Susceptibilty in Turkish
Population
Neslihan AYGÜN KOCABAS
Gazi University, Faculty of Pharmacy, Department of Toxicology
06330 Etiler, Ankara - Turkey
Abstract
The relationship among human genetic polymorphism, cancer
susceptibility is increasingly important for risk assessment, early diagnosis and
prevention, of clinical disease and cancer. This work analyses single nucleotide
polymorphism (SNP) in human xenobiotic and estrogen metabolising genes and it is
suggested that combinations of polymorphic enzymes may be better predictors of
cancer risk than polymorphisms in one or two genes alone.
Many of the low penetrance susceptibility genes involved in xenobiotic and
estrogen metabolism are polymorphically distributed within the human population. Single
nucleotide polymorphisms (SNPs) in these genes are great deal of attention has been paid to
the role in cancer epidemiology. Inherited alterations in the activity of cytochrome P450
1B1
(
CYP1B1),
Catechol
O
-methyltransferase (
COMT),
Manganese superoxide dismutase
(
MnSOD)
hold the potential to define differences in estrogen metabolism and, thereby,
possibly explain inter-individual differences in cancer susceptibility associated with
estrogen-mediated carcinogenesis The
CYP1B1
(L432V),
COMT
(V158M),
MnSOD
(Ala-
9Val) genotypes to examine estrogen metabolism and influence of age of menarche /
menopause, and N-acetlytransferase;
NAT2
(
*4, *12A, *5A, *5B, 5C, 6, 7
) genotypes to
detect environmental exposure were determined by using different polymerase chain
reaction-restriction fragment length polymorphisms (PCR-RFLP) based genotyping assays
in breast cancer patients and healthy women.
Sites in the DNA sequence where individuals differ at a single DNA base are called
single nucleotide polymorphisms (SNPs). Single nucleotide polymorphisms (SNPs) are the
most common genetic variations and occur once every 100 to 300 bases. Genetic variation
also plays a role in whether a person has a higher or lower risk for getting particular
diseases. Single gene differences in individuals account for some traits and diseases. More
complex interrelationships among multiple genes and the environment are responsible for
many common diseases, such as diabetes, cancer. In the postgenomicsera many more
discoveries will begin with elucidation of genetic polymorphisms in candidate genes (e.g.
those known to be involved in the metabolism, transport, or targets of the candidate
medication) >1@. The analysis of SNPs within gene participating in the metabolism of
