Abstract
Metformin is an antidiabetic drug with reported potential antiproliferative activity against different cancer types including breast cancer. However, the mechanism of action of how metformin can induce its antiproliferative activity is still unclear. Thus, the current study is a systematic review of the literature aiming to explore the reported antiproliferative mechanisms of metformin against breast cancer. The study included seventeen research articles that describe different mechanisms of action against breast cancer. While the majority of the studies confirm the antiproliferative potential of metformin, albeit at different potencies, there appear to be various mechanisms and factors that can influence this effect. There are a number of questions yet to be answered pertaining the use of metformin as an anti-cancer agent, warranting further investigation into this emerging area of research.