Anti-cancer Efficacy of Metformin: Recent Updates on Breast and Other Cancers

Purpose of Review Metformin is widely used for the management of pre-diabetes and type 2 diabetes (T2D). In recent times, metformin has also been the focus of intensive research in the field of cancer prevention because various preclinical and clinical study outcomes have associated its intake with a decrease in cancer incidence and anti-cancer benefits. Notably, the cancer-preventive and anti-cancer effects of metformin have been attributed to its potential to target metabolic syndrome-associated physiological aberrations, such as its capacity to lower blood insulin and glucose levels, particularly in malignancies that have been associated with hyperinsulinemia and hyperglycemia. Whether these cancer-protective benefits can also be extended to patients not afflicted with metabolic syndrome or non-T2D cohorts is still not clear. Thus, the role of metformin in cancer prevention and intervention across the molecular, genetic, epigenetic, and translational spectrum must be elucidated in depth to address apprehensions about its use as a pan-cancer intervention agent. This review will assist in recognizing the established benefits as well as the limitations related to the advancement of metformin as an effective anti-cancer drug. Recent Findings This review summarizes recent advances in metformin-centered pre-clinical and clinical research in an effort to delve into these unanswered questions and present an unbiased, focused perspective on the anti-cancer benefits of metformin in different cancers (with a focus on breast cancer). Summary The evidence of metformin’s cancer benefits cannot be overlooked and indicates its high pleiotropic potential to be an effective cancer prevention/intervention drug against breast cancer.