IGF1 and breast cancer: For instance, the Endogenous Hormones and BC Collaborative Group reported an odds ratio (OR) of 1.25 for an 80th percentile difference in IGF-1 levels, whereas the hazard ratio (HR) in the UK Biobank analysis increased from 1.26 to 1.37 after corrections, underscoring the significant risk posed by elevated IGF-1 [67].