XPO1 and renal cell carcinoma: Both when incubated in vitro in several RCC cell lines and when orally administered in vivo in a human mouse RCC xenograft, KPT-330 increased nuclear p21 through specific inhibition of XPO1, resulting in a significant decrease of RCC cell viability through cell cycle arrest (and inhibition of proliferation in vivo) and induction of apoptosis.