Correlation of mTOR and MRP1 Expression in Patients with Diffuse Large B-cell Lymphoma

Objective To investigate the expression and significance of the mammalian target of rapamycin(mTOR) and multidrug resistance protein 1(MRP1)gene in patients with diffuse large B-cell lymphoma(DLBCL). Methods A total of 109 patients with DLBCL diagnosed from Jan., 2010 to Jun., 2013 were collected from the Affiliated Tumor Hospital, Xinjiang Medical University. The expression of phosphorylated mTOR(p-mTOR) protein and MRP1 mRNA were examined by Western blot and RT-PCR, respectively. Kaplan-Meier method was used for survival analysis. Results The expression of p-mTOR and MRP1 mRNA were 58.7% and 56.9%, respectively(P=0.003). The expression of p-mTOR and MRP1 mRNA in non-germinal center B-cell like(non-GCB) subgroups were significantly higher than those in GCB subgroups(P<0.05). At a median follow-up of 18 months (range 2-52 months), the 3-year progression-free survival (PFS) of patients with positive and negative p-mTOR expression were 23% and 69%(P=0.003). The 3-year PFS of patients with positive and negative MRP1 expression were 39% and 62%(P=0.042). Conclusion Activation of mTOR signaling pathway and MRP1 overexpression play important roles in the development of DLBCL, moreover, MRP1 expression is closely related to mTOR expression.