Earlier work, including that led by the fellow during her PhD, suggests a higher melanoma risk in women with endometriosis, a prevalent and potentially debilitating disease with unknown aetiology. A genetic link has been speculated as pigmentary traits consistently associated with melanoma were also found to be associated with endometriosis risk. The present project will expand upon this intriguing but sparse scientific inquiry.The proposed research will combine cutting-edge genetics and genomics with traditional epidemiology to investigate the genetic overlap between endometriosis and melanoma in the Nurses’ Health Study (NHS) I & II, 2 prospective cohorts of 122,000 and 116,000 US nurses, respectively; and the “Etude Epidemiologique aupres de femmes de l’Education Nationale” (E3N), a prospective cohort involving 100,000 French women from the National Education System.The project will involve an outgoing phase of 24 months at the Channing Laboratory, Brigham and Women’s Hospital & Harvard Medical School in Boston, USA, where analyses involving the NHS I & II cohorts will be performed; and a return phase of 12 months with the “Nutrition, Hormones and Women’s Health” Team of the Inserm U1018 Research Centre in Villejuif, France, where data from the E3N cohort will be analysed.This training experience will offer the fellow a unique opportunity to acquire new skills by learning emerging genetic epidemiology techniques while collaborating with one of the leading institutions in the field. The project will highly benefit the European community by providing the candidate with expertise in state-of-the-art methodologies in a fast evolving and important area of research, and by significantly contributing to increase the available knowledge on the aetiology of melanoma and endometriosis, two major health burdens in Europe.