In this study, urinary neutrophil gelatinase-associated lipocalin (NGAL), which is a well-known urinary marker of kidney injury (29) and graft dysfunction (30), was not identified despite the fact that it has been reported to be detected in urine exosomes by ELISA (31) and also by us in the mass spectrometric analysis of soluble proteins in the urine (13). The gene discussed is LCN2; the disease is kidney injury.