TEK is a novel prognostic marker for clear cell renal cell carcinoma

OBJECTIVE: Clear cell renal cell carcinoma (ccRCC) is the most common type of kidney cancer. However, effective therapeutics for ccRCC are lacking. Novel biomarkers could provide critical information when determining prognoses for patients with ccRCC. In this study, we sought to determine if the expression of receptor tyrosine kinase (TEK) could be a potential novel prognostic biomarker for ccRCC. TEK, originally identified as an endothelial cell-specific receptor, plays an important role in the modulation of vasculogenesis and remodeling. Altered TEK expression has been observed in tumor tissues (e.g., oral squamous cell carcinomas, leukemia) and breast, gastric and thyroid cancers. However, the role of TEK in ccRCC remains unknown. PATIENTS AND METHODS: Differential TEK expression between non-metastatic (stage MO) and metastatic (stage M1) ccRCC patient cohorts was determined from The Cancer Genome Atlas (TCGA) and the International Cancer Genome Consortium (ICGC). Furthermore, TEK expression was assessed as a prognostic factor using the time-dependent area under the curve (AUC) of Uno's C-index, the AUC value of the receiver operating characteristics (ROC) at 5 years, Kaplan-Meier survival curves and multivariate analyses. RESULTS: A Kaplan-Meier curve analysis revealed that the downregulation of TEK expression was associated with a poor prognosis for patients with ccRCC with good discrimination (p<0.0001 and p=0.0044 for the TGCA and ICGC cohorts, respectively). Analyses of C-indices and receiver operating characteristic AUC values further sup- port port this discriminative ability. Moreover, multivariate analyses showed the prognostic significance of TEK expression levels (p<0.001). CONCLUSIONS: Although additional clinical investigations will be needed, our results suggest that TEK is a potential biomarker for ccRCC.