High c-Cbl expression in gliomas is associated with tumor progression and poor prognosis

Casitas B-lineage lymphoma (c-Cbl) expression has been linked to the development of several types of cancer. However, no studies on the association of c-Cbl and glioma have been published thus far. The present study examined glioma samples obtained from 136 patients treated at The First Hospital of China Medical University (Shenyang, China) from January 2007 to December 2009, and the expression levels of c-Cbl in the samples were evaluated by reverse transcription-quantitative polymerase chain reaction, immunohistochemistry and western blotting. Kaplan-Meier survival curves were generated and subjected to Cox regression analysis. The messenger RNA and protein levels of c-Cbl were observed to be upregulated in high-grade glioma, compared with low-grade glioma. A multivariate analysis revealed that the protein levels of c-Cbl were independently associated with overall survival [hazard ratio (HR)=4.923, 95% confidence interval (CI)=3.163-7.662; P<0.001]. Furthermore, the grade of the glioma (according to the World Health Organization criteria) was observed to be independent prognostic factors for progression-free survival and overall survival time (HR=8.842, 95% CI=7.827-9.989; P<0.001, and HR=10.247, 95% CI=9.009-11.655; P<0.001, respectively). Kaplan-Meier analysis and log-rank test indicated that high protein expression levels of c-Cbl were significantly associated with overall and progression-free survival (P<0.001). To the best of our knowledge, these results provide the first evidence that the overexpression of c-Cbl is correlated with advanced clinicopathological features and poor prognosis in patients with glioma.