Metabolomics study on the biochemical profiles of odor elements in urine of human with bladder cancer

It has been reported that dogs are capable of identifying cancer in humans by detecting a specific odor: bladder cancer by detecting urine odor and other cancers by detecting exhaled breath odor. However, no odor recognized by dogs that indicates cancer has been identified. In this study, we examined whether bladder cancer could be detected by gas chromatography-mass spectrometry (GC-MS)-based metabolomics analysis of urine odor. Nine patients with bladder cancer and 7 healthy controls were recruited as participants. Patients collected urine 3 d before and for 3-7 d after surgery. The concentrated urine odor was analyzed by GC-MS and principal component analysis (PCA). Results indicated 12 metabolites of urine odor. Score plots of 7 of the preoperative bladder cancer patients were clearly different from those of controls on the PCA map. The distribution of controls was in the negative domain of principal component (PC) 1, whereas the distribution of preoperative patients was in the positive domain of PC1. Bladder cancer was diagnosed in 5 of the 9 patients on the basis of urinary cytology. The findings indicate the potential to screen bladder cancer by analyzing urine odor. Moreover, diagnosis of bladder cancer on the basis of urine odor might have higher sensitivity than screening by urinary cytology.