Anticancer Potential of Isoflavones: A Narrative Overview of Mechanistic Insights and Experimental Evidence from the Past Ten Years

Isoflavones are natural compounds abundantly found in soybeans, recognized for their anticancer potential, primarily through their activity as phytoestrogens, which inhibit estrogen receptors. Because cancer remains one of the leading causes of mortality worldwide, identifying compounds that may complement chemotherapy is of great interest. In this review, we summarize advances reported over the past decade regarding the antitumor properties of isoflavones, with emphasis on both in vitro and in vivo effects, as well as chemical, botanical, and pharmacological aspects. A literature search was conducted using the PubMed database covering studies published from January 2014 to April 2025 using the following keywords: 'isoflavones' and 'anticancer', 'antitumoral', and 'antiproliferative' and 'cytotoxicity'. Genistein and daidzein emerge as the most extensively studied isoflavones, with well-documented anticancer activity. Reported anticancer effects include induction of apoptosis, ROS generation, cell cycle arrest, inhibition of cell migration and invasion, loss of mitochondrial membrane potential, modulation of estrogen-related pathways, and antiangiogenic activity. In addition to these mechanistic findings, several isoflavones demonstrated significant tumor growth inhibition in xenograft models, reinforcing their translational potential. Additionally, synergistic interactions with chemotherapeutic drugs and natural compounds and new drug delivery systems have been described. Breast and prostate cancer cell lines were the most investigated due to isoflavones' estrogen-like effects. However, the cell death mechanisms of newly discovered compounds still require further investigation.