Pathway Aromatase Inhibitor Pathway (Breast Cell),
Pharmacodynamics  Summary of pathways of estrogens and
antiestrogens. Aromatase Inhibitor Pathway (Breast Cell),
Pharmacodynamics hsd17b1 cyp19a1 cyp19a1 hsd17b1 esr1 esr2 serms
aromatase inhibitors clickable pathway icons   Approximately
two-third of breast tumors are estrogen receptor and/or
progesterone positive, and intensive research over the years
have established that estrogen plays a key role in initiating
and promoting breast cancer and that about 60-70% of these
tumors respond to endocrine treatment that reduce the effects of
estrogen. Once synthesized by the aromatase enzyme from
androgens, they bind to estrogen receptors (ERb and ERa),
recruit appropriate coactivators or corepressors leading to
dimerization, conformational change and binding to estrogen
response elements (EREs) upstream of estrogen responsive genes.
This leads to increased expression of genes responsible for cell
proliferation in breast tissue.  Two major pharmacologic
strategies