XPO1 and neoplasm: Most importantly, and consistent with the evidence that miR-34a positively modulates the activity of anti-cancer drugs in experimental models of different human tumor types [29], we showed that the miRNA was able to markedly improve the anti-proliferative and anti-tumor activity of selinexor in the MDA-MB-231 TNBC model, which is poorly sensitive to the XPO1 inhibitor as single agent.