SKP2 and pituitary tumor: miR-186 targets SKP2, which inhibits expression of p27, a negative regulator of G1 cell cycle progression, increasing proliferation. In human pituitary tumors, miR-186 and p27 expression is downregulated, while SKP2 expression is upregulated (240). In vitro, SKP2 overexpression decreases p27 expression and increases cell growth (240).