MDM2 and renal carcinoma: Considering that the Bax/Bcl2 ratio (2.84, 139.5%/49.1%) was higher in miR-4521 overexpressing cells than (2.50, 137.8%/55.0%) in si-FAM129A knockdown cells (Fig. 7), this phenomenon seems reasonable and also suggests the existence of other signaling pathways of miR-4521 in mediating renal cancer cell growth except for MDM2/p53/Bcl2/Bax.