Targeting Estrogen Pathways in Breast Cancer: A Review of Current Therapies and Emerging Strategies

Breast cancer continues to be the most commonly diagnosed cancer among women worldwide, with estrogen receptor-positive (ER +) types making up the largest portion. At the heart of this subtype is the estrogen signaling pathway, especially the estrogen receptor alpha (ERα), which plays a major role in the development, growth, and response to these cancers. This review takes a close look at the structure and function of estrogen receptors and how they influence cancer progression. We explore current treatment strategies-including well-known drugs such as Tamoxifen and Fulvestrant, as well as aromatase inhibitors-and explain how these therapies work and why resistance sometimes develops. This review also dives into newer, more targeted options, such as HER2 inhibitors, CDK4/6 blockers, and drugs that interfere with the PI3K/AKT/mTOR pathway. These treatments are changing the game for many patients. In addition, the review highlights exciting progress in drug design, showing how researchers are improving the precision and effectiveness of cancer medications through innovations in medicinal chemistry. Antibody-drug conjugates (ADCs) are being developed to deliver powerful drugs directly to cancer cells with fewer side effects. This article also looks at emerging approaches, like oral estrogen receptor degraders (SERDs), combination therapies, and precision medicine techniques that tailor treatment based on each patient's unique genetic profile. Altogether, these developments represent a major step forward in our understanding and treatment of ER+ breast cancer.