OBJECT: This study aimed at investigating the clinical significance and 
biological function of ubiquitination factor E4B (UBE4B) in human renal cell 
carcinoma (RCC).
METHODS: 19 paired clear cell renal cell carcinoma (ccRCC) tumor samples and the 
matched neighboring non-tumor samples were used to detect the expression of 
UBE4B in RCC tumor by Western blotting and RT-qPCR. UBE4B expression was also 
detected in 151 ccRCC paraffin-embedded tumor samples by using 
immunohistochemistry. Overall survival (OS) in different UBE4B expression groups 
were compared with Log rank test. The prognostic value of UBE4B expression in OS 
was evaluated with the univariate and multivariate Cox regression models. UBE4B 
was knocked down by small interfering RNA (siRNA) technology, and the effect of 
UBE4B on cell proliferation, colony formation, metastasis, apoptosis and cell 
cycle of RCC cells were examined in vitro.
RESULTS: Both protein and mRNA levels of UBE4B were up-regulated in ccRCC tumor 
tissues in contrast to the corresponding adjacent nontumor ones. UBE4B 
expression was positively associated with tumor-node-metastasis (TNM) stage and 
distant metastasis in ccRCC patients. Survival analyses indicated that low 
expression of UBE4B was associated with increased OS in ccRCC patients. 
Functional analyses demonstrated that siRNA silencing of UBE4B expression in 
SKRC39 and ACHN cells further reduced the growth, motility and invasiveness of 
RCC cells. Moreover, siRNA silencing of UBE4B in the RCC cell lines did not 
induce apoptosis, and an increase in the cell population was observed during the 
G0/G1 phase of the cell cycle.
CONCLUSION: UBE4B might act as an oncogene in regulating RCC development. 
Therefore it could be served as an effective indicator to predict OS and a 
potential biomarker for targeted therapy of RCC patients.