ASSOCIATION OF ESTROGEN RECEPTOR Α PVU II AND XBAI GENE POLYMORPHISMS WITH BREAST CANCER RISK; RELATION TO THE AGE OF MENARCHE AND MENOPAUSE

The association of estrogen receptor-α (ER-α) genetic polymorphisms with the risk of
breast cancer attracts much attention because ER functions as a hormone-dependent
transcriptional regulator, which in turn, plays a significant role in the development of
breast cancer. This study was conducted to find if there is an association between
genetic polymorphisms in the ER-α gene and breast cancer in Egyptian females and
its relation to the age of menarche and menopause. A total of 50 breast cancer
Egyptian women and 25 age-matched healthy controls were involved in the study.
PvuII and XbaI polymorphisms of ER-α gene were genotyped by polymerase chain
reaction restriction fragment length polymorphism. Pp/pp genotypes were found in
84% of patients and in 56% of controls; and the homozygous wild PP genotype was
found in 16% of patients, and 44% of controls. There was highly significant increase
in the risk of breast cancer with the presence of PvuII restriction site (Pp/pp
genotypes) compared with absence of restriction site (PP genotype) (P = 0.008).
There was statistically significant decrease in the age of menarche (P = 0.021) and
insignificant differences in the age of menopause of all participant women with
presence of PvuII restriction site. Xx/xx genotypes were found in 84% of patients and
in 76% of controls; and XX genotype was found in 16% of patients and in 24% of
controls. There was insignificant difference in genotype frequency of the ER-α XbaI
polymorphism between patients and controls (P = 0.157). There was statistically very
highly significant decrease in the age of menarche (P<0.001) and insignificant
differences in the age of menopause of all participant women with presence of XbaI
restriction site. From the present study, it could be concluded that genetic
polymorphisms in the ER-α gene may play a role in the etiology of breast cancer in
Egyptian women and may be a genetic determinants of the age of menarche.