This phase II trial studies how well metformin hydrochloride works together with doxycycline
in treating patients with localized breast or uterine cancer. Metformin hydrochloride may
stop the growth of cancer cells by blocking some of the enzymes needed for cell growth.
Doxycycline may stop the growth of bacteria by keeping them from making proteins and
minimized the toxic side effects of anti-cancer therapy. It is not yet known whether giving
metformin hydrochloride together with doxycycline may be a better way in treating patients
with localized breast or uterine cancer.