We then analyzed the correlation between renal fibrosis and serum HE4, as shown in Figure 2A; a significantly positive correlation was observed when renal fibrosis was plotted against HE4 levels (two-tailed Spearman's correlation, r = 0.938, P < 0.0001), and serum HE4 levels were obviously elevated with IF/TA fibrosis grade (serum HE4 levels of normal control, IF/TA 0, 1, 2 and 3: 35.9, 45.0, 131.5, 234.0, and 615.0, pmol/L, P < 0.0001). Here, WFDC2 is linked to renal fibrosis.