XPO1 and cancer: The XPO1 expression was variable and different between the normal tissue samples, the primary tumors, and the metastatic samples (Figure 1A), with an increasing gradient from normal samples to primary cancer samples (p = 4.88 × 10−18, Student t-test), and from primary cancer samples to metastatic samples (p = 1.22 × 10−21, Student t-test).