A lower risk of dying from urological cancer in Down syndrome: clue for cancer protecting genes on chromosome 21.

OBJECTIVE It was the aim of this study to evaluate the risk of dying from bladder and kidney cancer in persons with Down syndrome (DS), as compared with the general population. METHODS Using data of the French national mortality statistics (INSERM) during a 21-year period, 1979-1999, we compared the observed number of deaths from renal and bladder cancer in DS subjects with the expected number of deaths from these cancers. The expected number of deaths was calculated taking into account the prevalence of DS at birth and the life expectancy of persons with DS, assuming the risk was identical to the one of the general population. RESULTS A significant 6-fold decreased risk of dying from urological cancer was found in persons with DS, with 5 cases observed, while 30 were expected. The relative risk of dying was 0.27 for bladder cancer (p = 0.0017) and 0.06 for kidney cancer (p < 0.0001). Other mortality studies provided similar values. CONCLUSIONS Children and adults with DS have a decreased risk of dying from urological neoplasms. Genes on chromosome 21 could play a protective role against urological cancer.