Expression and clinical significance of ubiquitin‑specific‑processing protease 34 in diffuse large B‑cell lymphoma

Ubiquitin‑specific‑processing protease 34 (USP34) is a deubiquitinase that is involved in the pathogenesis of various cancers. Its roles in diffuse large B‑cell lymphoma (DLBCL) are unknown. The present study aimed to determine the level of USP34 expression and to explore its association with clinicopathological features and prognosis in patients with DLBCL; a total of 30 cases of reactive lymphoid hyperplasia and 131 cases of DLBCL were included in this study. The level of USP34 expression was examined by immunohistochemistry (IHC), and correlations between USP34 expression and clinicopathological features and prognosis were analyzed. In addition, mutations, expression and clinical significance of USP34 in DLBCL were evaluated using data from The Cancer Genome Atlas (TCGA). USP34 expression was significantly higher in DLBCL compared with expression in reactive lymphoid hyperplasia. In DLBCL, overexpression of USP34 was associated with older age, germinal center B cell‑like (GCB) subtype, multiple extranodal involvements and higher International Prognostic Index (IPI) scores. No significant association was identified between USP34 protein level and patient survival. In the TCGA dataset, low USP34 mRNA expression was demonstrated to be associated with a poor disease‑free survival (DFS), but not with overall survival (OS) in patients with DLBCL. In conclusion, high expression of USP34 protein in DLBCL was associated with older age, GCB subtype, multiple extranodal involvement and high IPI scores of DLBCL. USP34 may be a valuable marker for the assessment of patients with DLBCL, and further studies are needed to clarify USP34 expression on DLBCLs.