The goal of this study to investigate the volatile organic compounds (VOCs) in the urine samples of both healthy individual and bladder cancer patients, using gas chromatography - mass spectrometry. Researchers aim to find a set of certain VOCs specific to bladder cancer and use this set to construct a diagnostic model that can help diagnosing bladder cancer. Participants will be asked to collect their early morning midstream urine in a predesignated container. Researchers will compare urine VOCs from bladder cancer patients and healthy individuals to see if there is any VOC whose concentration differ significantly among the two groups.

Specifically, participants will be asked to collect 35-45 ml of their early morning midstream urine sample in a predesignated polytetrafluoroethylene bottle. Researcher will collect participants' health information, including their: 1)smoking history; 2)comorbidity; 3) history of past urological procedure; 4)medication; 5)pathology diagnosis after surgery, if participants have bladder cancer.

Inclusion Criteria:

• bladder tumor confirmed by cystoscopy and radiology
• women of childbearing age with negative urine pregnancy test result
• willing to participate in this trial and sign the informed consent form

Exclusion Criteria:

• patient with 1) uncontrollable urinary tract infection; 2) severe systemic disease; 3) history of malignancy within the past 5 years; 4) pregnancy or lactation
• patient involved in other clinical trials
• other situations researcher considered to be ineligible for this trial

Inpatients with confirmed bladder tumor, present in first affiliated hospital of Xi'an jiaotong university during the recruitment phase, are recruited. Healthy volunteers are recruited outside the hospital with invitations to participate.