Received: 16 April 2021
Accepted: 21 April 2021
First Online: 5 May 2021
: Cases with bladder cancer and controls were recruited from two different hospitals in the same city. The bioethics committees of Dong-A University Hospital, Pusan National University Hospital approved research plan and procedure: [Dong-A University Hospital (#IRB-07-10-7; Busan, Korea), Pusan National University Hospital (#IRB-H-1706-002-007; #IRB-H-1804-002-065; Busan, Korea)].
: Not applicable.
: The authors claim that they do not have any conflict of interest.