WFDC2 and renal fibrosis: HE4 indirectly inhibits the degradation of type I collagen (Nagy et al., 2016; Wang et al., 2019) and causes infiltration and polarization of M2 macrophages (Rowswell-Turner et al., 2021), which could promote the progression of renal fibrosis (Jiao et al., 2021a; Jiao et al., 2021b; An et al., 2023).