Figure 3.
A comprehensive model for breast cancer. Applying a stem cell model to breast cancer helps explain much of the known data. The major risk factors are hormonal and
can act to influence the number and activation of stem cells. Useful prevention strategies inhibit estrogen production or
action. BRCA1 and BRCA2 germline mutations increase the likelihood of P53 inactivation (directly or through inhibition of DNA repair), but the BRCA genes are outside of the main pathway and thus
are not found in most sporadic tumors.