Bladder cancer, the most common type being transitional cell carcinoma, has an increased risk if both copies of the GSTM1 gene are deleted or their are mutations in NAT2.
The most common type is transitional cell carcinoma. Deletion of both copies of the GSTM1 gene has a modest increase in risk of bladder cancer. Similarly, mutations in NAT2 (N-acetyltransferase) is associated with increased risk for bladder cancer. 
