PTEN and Hyperoxaluria: It prompts us to believe that, no matter whether mediated by hypercalciuria or hyperoxaluria, miR-21 was the common miRNA that was overexpressed in the process of stone formation, which might subsequently cause oxidative stress or stimulate renal tubular epithelial cells apoptosis and tubulointerstitial fibroblast proliferation, thus resulting in the fibrotic dysfunction of kidney by certain downstream signaling pathways such as PTEN/Akt pathway [23].