A Correlative Study of Estrogen Receptor Signaling: Molecular and Histological Perspectives in ER-Positive Breast Tumors
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April 1, 2026Sajjad Jawad Kadhim
Department of Biology, College of Education for Pure Sciences, University of Wasit, Iraq
ِAbstract
Breast tumor remains the most widespread and lethal malignancy affecting women worldwide.
Approximately two-thirds of cases are classified as hormone receptor-positive, characterized by the
expression of estrogen and progesterone receptors, and are closely regulated by estrogen signaling
pathways. The primary therapeutic approach for these tumors involves antiestrogen agents; however,
resistance to such treatments inevitably develops due to various molecular mechanisms. These include
aberrant activation of the PI3K signaling cascade, mutations in the ESR1 gene, functional alterations of
estrogen receptors, and disruptions in cell cycle regulation. In response to these challenges, novel
therapeutic strategies have emerged, such as selective estrogen receptor degraders (SERDs) and
combination regimens incorporating cyclin-dependent kinase (CDK) 4/6 inhibitors or PI3K pathway
inhibitors. A comprehensive understanding of estrogen receptor biology is therefore essential for
optimizing treatment outcomes and guiding the development of next-generation therapies. This study
highlights current advances in the molecular mechanisms, signaling dynamics, and clinical implications
of estrogen receptor activity in hormone-dependent breast cancer.
