Table 1.

Summary of epidemiological in vivo and in vitro studies done with metformin in different cancers

Type of cancerConclusionsEpidemiological studiesPreclinical studiesIn vitro studies
ProstateMetformin is associated with a reduction of prostate cancer incidence(66)
Metformin inhibits human prostate cancer cell (LNCaP, PC3, and DU145) proliferation and tumor growth via inhibition of cyclinD1(25)(25)
Metformin inhibits PC3 proliferation(22)
BreastHigher response to chemotherapy in patients treated with a combination of metformin and chemotherapy(67)
Metformin inhibits the development of mammary tumors in HER-2/neu mice(40)
Metformin growth inhibition is mediated by AMPK(22)
Metformin inhibits translation initiation in a LKB1/AMPK–dependent way(21)
Metformin blocks cell cycle progression at S phase and induces apoptosis in triple-negative breast cancer cells(35)(35)
Human genome array of metformin-responsive genes in MCF-7, SKBR3, and MCF-7/HER2(64)
Metformin induces cell cycle arrest in MCF-7, BT-474, and SKBR-3(34)
Metformin restores lapatinib sensitivity in MCF-7/HER2 LapR(65)
Metformin suppresses erbB-2 expression via inhibition of mTOR in SKBR3 and MCF-7/HER2(37)
Metformin induces cell cycle arrest and cyclin D1 inhibition in MDA-MB-231 cells(32)
Metformin inhibits MDA-MB-435 cancer cell growth but promotes angiogenesis and tumor growth in vivo(43)(43)
Metformin selectively kills cancer stem cells at low doses (0.1-0.3 mmol/L). Synergistic effect of doxorubicin and metformin(33)(33)
PancreasMetformin use is associated with reduced risk of pancreatic cancer(68, 69)
Metformin prevents carcinogen-induced pancreatic cancer induction in hamsters(39)
Metformin disrupts the crosstalk between G protein-coupled receptors and insulin receptor signaling and inhibits cancer cell and tumor growth(38)(38)
Metformin induces apoptosis in ASPC-1, BxPc-3, PANC-1, and SW1990(36)
ColonMetformin use is associated with reduced risk of colon cancer(69)
Metformin inhibits tumor growth in HCT116 P53−/− cells and induces autophagy in a p53-dependent way(31)(31)
LungMetformin attenuates the effect of a high-fat diet on mouse lewis lung carcinoma (LLCC1) xenograft(42)(42)
OvaryMetformin inhibits the proliferation of epithelial ovarian cancer cells OVCAR-3 and OVCAR-4(23)
Metformin acts through AMPK to inhibit ovarian cancer cell growth(70)