BRCA1/BRCA2 mutation- They act as tumor suppressor genes, since cancer arises when both alleles are inactive or defective-one caused by a germ-line mutation and the second by a subsequent somatic mutation
HER2/NEU proto-oncogene, which has been found to be amplified in up to 30% of invasive breast cancers. This gene is a member of the epidermal growth factor receptor family, and its overexpression is associated with a poor prognosis
Women are more likely to carry a breast cancer susceptibility gene if
1.they develop breast cancer before menopause,
2.have bilateral cancer,
3.have other associated cancers (e.g., ovarian cancer),
4.have a significant family history (i.e., multiple relatives affected before menopause), or
belong to certain ethnic groups.
Li-Fraumeni syndrome (caused by germ-line mutations in p53
Cowden disease (caused by germ-line mutations in PTEN
carriers of the ataxia-telangiectasia gene
amplification of RAS and MYC genes
Mutations of the well-known tumor suppressor genes RB and p53 may also be present.
Risk factors contd….
Prolonged exposure to exogenous estrogens
postmenopausally, known as hormone replacement therapy
Oral contraceptives: balanced low doses of combined estrogens and progestins seem to be safe
long duration of reproductive life,
late age at birth of first child
20% to 30% of women irradiated for Hodgkin lymphoma in their teens and 20s develop breast cancer, but the risk for women treated later in life is not elevated
obesity, alcohol consumption, and a diet high in fat.