TGF-β-activated Kinase-1: A Potential Prognostic Marker for Clear Cell Renal Cell Carcinoma

Background: TGF-β-activated kinase-1 (TAK1) has been found to be over-expressed in a variety of solidmalignancies and related to tumor growth. The aim of this study was to evaluate the expression level of TAK1in clear cell renal cell carcinoma (ccRCC) and assess its value as a novel prognostic marker.
Methods: TAK1mRNA was assessed in 51 paired ccRCC tissues and adjacent normal tissues (ADTs) by real-time PCR. TissueTAK1 protein was also assessed in 91 ADTs and 177 samples of ccRCC immunohistochemically for evaluationof relationships with clinical characteristics.
Results: RT-PCR showed that TAK1 RNA level was significantlyhigher in ccRCC tissues than in the paired ADTs and immunohistochemistry confirmed higher expression ofTAK1 protein in ccRCC samples compared with ADTs. TAK1 protein expression in 177 ccRCC samples wassignificantly correlated with T stage, N classification, metastasis, recurrence and Fuhrman grade, but not ageand gender. Patients with low TAK1 levels had a better survival outcome. TAK1 expression and N stage wereindependent prognosis factors for the overall survival of ccRCC patients.
Conclusions: Overexpression of TAK1predicts a poor prognosis in patients with ccRCC, so that TAK1 may serve as a novel prognostic marker.