[Clinical Significance of XPO1 High Expression in Diffuse Large B-Cell Lymphoma and Its Mechanism].

Objective: To explore the expression and clinical significance of XPO1 in newly diagnosed adult diffuse large B-cell lymphoma (DLBCL), and further investigate its functional mechanism.

Methods: Immunohistochemical testing was conducted for XPO1 expression in 93 cases of DLBCL and 30 cases of reactive lymphoid hyperplasia. A risk model was construed to find survival related genes in DLBCL patients. Cell proliferation, apoptosis, and cell cycle assays were performed to explore the effect of XPO1 inhibitor (KPT-8602) and XPO1 knockdown. Differential expression gene (DEG) was examined based on the transcriptomes.

Results: The expression of XPO1 in DLBCL patients was higher than that of the controls. Compared with XPO1 low-expression group, XPO1 high-expression group had a worse prognosis. The constructed risk model indicated that XPO1 and 14 genes in nucleocytoplasmic transport pathway (NTP) might be potential prediction marker of adverse outcome in DLBCL. Moreover, KPT-8602 as well as the XPO1 knockdown could inhibit cell proliferation, promote apoptosis, and induce cell cycle arrest in two DLBCL cell lines, Farage and SU-DHL-4. Based on the gene expression profiling in the datasets of DLBCL, patients were classified into XPO1 high and XPO1 low expression groups, and the MYBL1 was identified as the down-stream effector of XPO1. Inhibiting the function of XPO1 or reducing its expression can significantly decrease the expression of MYBL1 Conclusion: XPO1 is highly expressed in DLBCL, which is associated with poor prognosis. The oncogenic roles of the new XPO1/MYBL1 signaling are identified in DLBCL and XPO1 inhibitor may be a potential option for newly-diagnosed DLBCL patients.