PCOS Serum Promotes Endometrial Cancer Cell Proliferation with Partial Involvement of IGF-Associated AKT/mTOR Signaling: A Pilot Translational Study with Exploratory Molecular Insights

Women with polycystic ovary syndrome (PCOS) have a substantially increased risk of endometrial cancer (EC), yet the biological mechanisms underpinning this association, to support future prevention and therapeutics, remain incompletely understood. Insulin-like growth factor (IGF)-associated signaling has been implicated, but existing evidence is conflicting. In this pilot translational study, serum IGF1 and IGFBP-3 were measured in women with PCOS (n = 12 for IGF1 and n = 6 for IGFBP-3) and controls (n = 24 for IGF1 and n = 7 for IGFBP-3). Pooled serum, stratified by IGF bioactivity, was applied to human EC cells to further assess effects on cell viability, cell cycle distribution, and downstream signaling. Computational analysis of publicly available endometrial cancer datasets was used to contextualize experimental findings. Serum IGF1 and IGFBP-3 levels did not differ significantly between PCOS and control groups. However, pooled PCOS serum was associated with increased EC cell viability, altered cell cycle progression and PI3K/AKT/mTOR signaling compared with control serum in this exploratory model. Pharmacological inhibition of IGF1R partially attenuated these effects, suggesting that IGF-associated pathways may contribute but are unlikely to act in isolation. In silico analysis identified frequent alterations in PI3K/AKT/mTOR-related genes in EC, consistent with pathway-level vulnerability rather than IGF1-specific dependence. These findings suggest that PCOS serum contains factors that are associated with increased EC cell viability and altered signaling pathways with partial involvement of IGF signaling; however, these findings should be interpreted cautiously given the exploratory pooled-serum design, small subgroup sizes, and use of a single EC cell line. However, multiple metabolic and hormonal pathways are likely to contribute. Larger, better-controlled studies incorporating insulin, sex steroids, and multiple EC models are required before causal inferences can be made.