As a protein biomarker in uEVs, Zhou et al. reported Wilms’ tumor 1 (WT1) transcription factor, which is widely recognized as a marker for differentiated podocytes, as a potential biomarker for early progression and treatment-induced regression of podocyte injury in childhood focal segmental glomerulosclerosis (FSGS) or steroid-sensitive nephrotic syndrome [26]. The gene discussed is WT1; the disease is focal segmental glomerulosclerosis.