Mosaic loss of chromosome Y in peripheral blood is associated with shorter survival and higher risk of cancer

Incidence and mortality for sex-unspecific cancers is higher among men and is largely unexplained1,2. Furthermore, age-related loss of chromosome Y (LOY) is frequent in normal haematopoietic cells3,4, but the phenotypic consequences of LOY have been elusive5–10. From analysis of 1153 elderly men, we report that LOY was associated with risks of all-cause mortality (HR=1.91, 95% CI=1.17-3.13, events=637) and non-haematological cancer mortality (HR=3.62, CI=1.56-8.41, events=132). LOY affected at least 8.2% of subjects in this cohort and median survival among men with LOY was 5.5 years shorter. Risk of all-cause mortality and LOY was validated in an independent cohort (HR=3.66), in which 20.5% of subjects displayed LOY. These results illustrate the impact of post-zygotic mosaicism on disease risk, could explain why males are more frequently affected by cancer and suggest that chromosome Y is important in processes beyond sex determination. LOY in blood could become a predictive biomarker of male carcinogenesis.