Cellular fibronectin in patients with transitional cell carcinoma of the bladder

Various tumor markers for transitional cell carcinoma (TCC) of the bladder have been described, but none of them are used in clinical routine. Fibronectin, a glycoprotein, seems to play a very important role in both the progression and invasion of cancer. The aim of this study was to evaluate cellular fibronectin (cFN) in the urine and blood of patients with TCC of the bladder and to determine its possible role as a tumor marker and prognostic factor. Morning urine samples and blood were collected from 20 patients (8 women, 12 men, mean age 69.9 years) before they underwent transurethral resection of bladder tumors (TURB). Twenty patients (10 women, 10 men, mean age 63.4 years) with nonmalignant urological disorders were recruited as the control group. Determination of cFN in plasma and urine was performed by using a newly developed time-resolved fluorescence immunoassay (TRFIA). Patients with nonmalignant diseases had mean cFN plasma levels of 404 ng/ml (range 181-746 ng/ml). Patients with TCC of the bladder showed significantly higher cFN plasma levels of 686 ng/ml (range 274-1999 ng/ml, p < 0.05). Subdivided according to the TNM system, muscle-invasive bladder tumors (n = 5) demonstrated higher cFN plasma levels (mean 944 ng/ml) than superficial bladder tumors (n = 15, mean 463 ng/ml). There were no differences of plasma cFN concentrations concerning tumor grade and also no differences in urine levels between the different groups. We found a significant difference (p < 0.04) of cFN plasma levels between patients with TCC of the bladder and the control group. The difference in cFN plasma levels between pTa/pT1 and greater than or equal topT2 tumors indicates a clinically useful potential of this tumor marker for preoperative staging and postoperative follow-up. Our data underline the important but still unclear role of cFN as a tumor marker in TCC, and this will be the focus of future studies.