Cancers develop for many years before they are diagnosed. Using data from first-generation ALSPAC offspring, we aim in this study to estimate the effects of being more genetically susceptible to endometrial cancer on metabolic and proteomic traits measured in blood across early life; this should help to reveal what early stages of endometrial cancer development look like and when they occur. More specifically, we will examine associations of genetic risk scores for endometrial cancer that has been shown to be influenced by obesity with traits from targeted metabolomics measured in childhood (age 8y), adolescence (age 15y), and young adulthood (age 18y and 24y) and proteomics measured in childhood (age 8 y) and young adulthood (age 24). This allows us to view subtle changes in the circulating metabolome and proteome over time which precede the onset of clinically detectable endometrial cancer by several decades. Recognizing the early signs of endometrial cancer development is vital for informing early detection, preventing its onset in older age, and improving survival.