Enhanced public awareness in recent years has contributed significantly to the detection of small carcinomas which are associated with a better prognosis. In addition, remarkable efforts have been made to detect risk factors that will help to identify those women most likely to develop breast cancer and the genes that contribute to these risks. Among various factors studied, age and gender plays an important role. The incidence of breast cancer increases with age and the rate is higher in the developed western world, i.e. North America and Northern Europe. Other risk factors include a personal history of prior breast cancer, family history of bilateral, premenopausal or familial cancer syndrome and atypical ductal hyperplasia, particularly if associated with family history.
Breast cancer occurs in both sporadic and inherited forms.
A breast cancer susceptibility gene named BRCA1 has recently been discovered. It is localized to the chromosomal region 17q 12 -q 21 on the long arm of chromosome 17. Shortly after this discovery, researcher announced the discovery of a second breast cancer gene, BRCA2, on the short arm of chromosome 13. This suggests that BRCA2, may also be an important breast cancer gene. The identification of susceptibility genes in high-risk families can assist in risk estimation for genetic counseling and also serve as a guide in choosing candidates for clinical trials of breast cancer screening and chemopresentation.