Tanaka et al. [32] found that increased TFF3 mRNA expression in renal biopsy specimens from patients with tubulointerstitial fibrosis in IgA nephropathy (IgAN) was associated with increased urinary TFF3 levels and that examination of urinary TFF3 levels may reflect interstitial tubular fibrosis in IgAN patients. Here, TFF3 is linked to IgA glomerulonephritis.