Cyclin-dependent kinase 5 acts as a promising biomarker in clear cell Renal Cell Carcinoma

This research provides the first evidence of CDK5 in ccRCC prognosis and correlation with different p21 expression in overall survival (OS) analysis.

The data from both of The Cancer Genome Atlas (TCGA) and Gene Expression of Normal and Tumor Tissue (GENT) were analyzed for determining the expression of CDK5 in kidney cancer. Tissue microarray that made by using 150 ccRCC samples was used in immunohistochemistry (IHC) analysis. A validation of OS cohort was extracted from Oncomine database.

The CDK5 expression was significantly lower in cancer tissue compared with normal in TCGA (p < 0.0001), GENT database also showed a relative low expression in kidney cancer. Among 150 ccRCC patients, low CDK5 was detected in 83 cases (55.3%), low p21 in 97 cases (64.7%). CDK5 was associated with the advanced TNM stage (p = 0.042), and Fuhrman grade (p = 0.035). Patients with lower CDK5 might be more likely to be aggressive status. According to the combination analysis of CDK5 and p21, patients in CDK5 low/p21 low group showed poorer survival rate, and no significant survival difference was observed in other groups. In the Cox multivariate analysis, the co-expression of CDK5 low/p21 low was identified as an independent prognostic factor in ccRCC patients.

Together, our findings provided the first evidence that CDK5 was acting as a promising biomarker in ccRCC patients, and co-expression of CDK5 and p21 is an independent prognostic for overall survival. IHC analysis of CDK5 and p21 on cancer tissues after surgery may help to evaluate and predict the outcome of ccRCC patients.