They were checked for peak shape, SWISS score, missing values in all the samples, etc. After this quality control, 69 proteins were kept as statistically relevant differentially expressed in the first biomarker discovery study for the first diagnosis of bladder cancer, and two proteins (HBB and HBA1) were retained as differentially expressed in the biomarker discovery for the detection of bladder cancer recurrence. Here, HBB is linked to urinary bladder cancer.