POSTN and focal segmental glomerulosclerosis: the study found that the expressions of periostin mRNA are significantly increased in pathological tissues such as focal segmental glomerulosclerosis, membranous nephropathy,lupus nephritis, etc. eGFR is negatively correlated to the transcription level of periostin.By immunohistochemistry, it was found that periostin is mainly expressed in the areas of mesangial hyperplasia and interstitial fibrosis, and the expression level is negatively correlated with renal function [38].