Breast cancer is one of the leading causes of cancer-relatedmor-
tality among women worldwide from different age groups. The
vast majority of breast cancers in postmenopausal women are
deriving from estrogens production.
1–3
Estrogens are biosynthe-
sized from androgens catalyzed by aromatase (CYP19), an enzyme
belonging to the P450 family of monooxygenase heme proteins.
Two main strategies to control or block breast cancer progression
include binding of the estrogen receptors (ERs) with receptor
antagonists (ERAs such as tamoxifen), and inhibiting the produc-
tion of estrogen with aromatase inhibitors (AIs).
3
AIs were found
to have less side effects than ERAs owing to the the lack of estro-
genic activity on uterus and vasculature.
3