Department of Urology, Kitasato University School of Science, Sagamihara, Japan
We investigated the urinary levels of 14-3-3 protein beta/alpha to evaluate their diagnostic significance with regard to clear cell renal cell carcinoma (ccRCC) and angiomyolipoma (AML). Urine samples from 91 patients with ccRCC, 16 patients with AML and 24 healthy volunteers were assessed. We used an enzyme-linked immunosorbent assay (ELISA) to quantify 14-3-3 protein beta/alpha levels in urine. Values were higher in patients with ccRCC than in those with AML and in healthy volunteers. High levels were associated with pathologic stage, lymph node status, distant metastasis and poor survival. Urinary levels of 14-3-3 protein beta/alpha were significantly increased in patients with small-sized carcinoma, irrespective of being less than 4.0 cm and 2.0 cm, compared with levels in patients with AML. This study is the first to report that increased expression of 14-3- 3 protein beta/alpha in urine is associated with advanced stage and poor survival in patients with ccRCC. In addition, urinary 14-3-3 protein beta/alpha may differentiate AML from RCC, even when small sized. These results suggest that examination of urinary 14-3-3 protein beta/alpha could serve as a diagnostic and prognostic marker in patients with ccRCC.