[Bladder cancer at an early age in father and son].

Bladder cancer may be caused by external factors like tobacco smoking, but may also be familial. We report on a father and son who developed this tumour at the ages of 45 and 35. Testing various genetic markers including the mismatch repair proteins MLH1, MSH2 and MSH6, whose loss is associated with a higher risk for hereditary non-polyposis colorectal cancer (HNPCC, Lynch syndrome), did not point to a familial disease. Thus the heavy smoking habits of the two patients must be considered as causal.