Insulin-like Growth Factor 1 (IGF1) and Its Isoforms: Insights into the Mechanisms of Endometrial Cancer

Endometrial cancer (EC) is a common gynaecological malignancy associated with metabolic dysfunctions such as obesity, diabetes and insulin resistance, as well as hormonal imbalances, particularly involving oestrogen and progesterone. These factors disrupt normal cellular metabolism, heightening the risk of developing endometrioid EC (EEC), the most prevalent subtype of EC. The insulin-like growth factor-1 (IGF1) pathway, a key regulator of growth, metabolism, and organ function, is implicated in EC progression. Recent research highlights the distinct roles of IGF1 isoforms, including IGF1-Ea, IGF1-Eb, and IGF1-Ec, in promoting tumour growth, metastasis, and hormone signalling interactions, particularly with oestrogen. This review examines the function and clinical significance of IGF-1 isoforms, emphasising their mechanisms in gynaecological physiology and their contributions to EC pathogenesis. Evidence from other cancers further underscores the relevance of IGF1 isoforms in driving tumour behaviours, offering valuable insights into their potential as biomarkers and therapeutic targets. Understanding these mechanisms provides opportunities for novel approaches to the prevention, diagnosis, and treatment of EC, improving patient outcomes and advancing the broader field of hormone-driven cancers.