The body's cells reproduce themselves throughout
your lifetime, as tissues wear out and their cells are
replaced in a controlled manner.
Brea.st cancer - like all cancers - occurs when that control is lost and cells begin to divide at an unusually high rate.
No single trigger or cause has been identified
for brea.st cancer. Certain risk factors exist, though, that increase a woman's chance of developing it:

1. age - it's more common in women over 50

2. family history - if a woman's mother or sister had
the disease before menopause, this is occasionally associated with one of two genes linked to breas.t
cancer
3. previous breas.t cancer
4. family history of ovarian cancer
5. age of pregnancy - women who haven't had
children, or whose first child was born after age 30

6. age of menstruation - starting periods at a young
age (under 12 years old)
7. entering menopause later (over age 55) increases
breas.t cancer risks
8. recent research suggests that women who start smoking regularly within 5 years of the onset of
their menstrual periods are 70% more likely to
develop breas.t cancer before the age of 50 than
non-smokers
having
9. dense breas.t tissue
10. radiation treatment to the chest, especially before 30
years of age
11. alcohol consumption contributes to the risk of breas.t
cancer

12. hormone replacement therapy (HRT; estrogen plus
progesterone) increases the risk of breas.t cancer
slightly after 5 years of therapy
13. oral contraceptives increase risks slightly, if used
over many years
14. Obesity with excess caloric and fat intake.