Urinary proteins as biological markers: bladder cancer diagnosis versus urinary tract infection

Urinary concentrations of the soluble adhesion molecule E-cadherin and total protein in patients with bladder cancer

Reduced expression of the adhesion molecule E-cadherin has been associated with increased invasiveness and poorer survival in patients with bladder cancer. We have examined soluble E-cadherin (sE-cadherin) and total protein concentrations in urine from patients with bladder cancer (n = 34), non-neoplastic benign urological diseases (n = 14) and healthy controls (n = 21) to determine their diagnostic and prognostic significance. Soluble E-cadherin concentrations of the cancer group were significantly higher (P < 0.001) than those of the controls but the benign group was not significantly different from either the cancer group or the controls. When sE-cadherin concentrations were adjusted for creatinine, similar but more statistically significant results were obtained and the benign group was significantly elevated compared with the controls (P < 0.01). No differences were apparent between the invasive (pT1-4) and non-invasive (pTa) cancers. Urinary total protein concentrations in the cancer group were significantly higher than the controls (P < 0.001) and the benign group (P < 0.05) although no difference was seen between the benign group and patients with non-invasive (pTa) cancer or between the benign group and controls. When expressed as the protein/creatinine index, results were similar but more statistically significant and a significant difference was seen between invasive and non-invasive cancers (P < 0.01). Only the protein/creatinine index correlated significantly with stage of the tumour (P < 0.01). It is concluded that urinary sE-cadherin measurements are of no greater value than urinary total protein.

Increased immunodetection of acidic fibroblast growth factor in bladder cancer, detectable in urine

Acidic fibroblast growth factor is a regulatory peptide involved in cell proliferation, differentiation and motility. We used a polyclonal antiserum raised against purified native bovine acidic fibroblast growth factor, with no cross-reactivity for basic fibroblast growth factor to detect acidic fibroblast growth factor in tissue extracts and urine samples by means of a competitive enzyme immunoassay. Histochemical analysis was also performed on 10 specimens of normal urothelium and 50 of bladder cancer. Acidic fibroblast growth factor immunoreactive material was found in normal urothelium (1.77 +/- 2 ng./gm. tissue) and was increased more than 10-fold in patients with transitional cell carcinoma of the bladder (20.36 +/- 12 ng./gm. tissue). Immunohistochemical analysis localized immunoreactivity in the epithelial compartment of bladder tumors. Acidic fibroblast growth factor was assayed in urine from 579 individuals comprising a control group (114) and patients with benign prostatic hypertrophy (133), carcinoma of the prostate (96) or transitional cell carcinoma of the bladder (236). There was a significant difference in the frequency of urinary acidic fibroblast growth factor detection among the patients with invasive transitional cell carcinoma, the control group (p < 0.001) and the patients with prostatic disease (p < 0.01). The sensitivity was 72% and the specificity was 91%. Furthermore, the frequency of acidic fibroblast growth factor detection by enzyme immunoassay in the urine and the intensity of immunostaining was correlated with the stage of the disease. These data strongly suggest that acidic fibroblast growth factor is a potential marker for bladder tumors that may be of use in the noninvasive followup of patients with bladder cancer. We present a simple and reliable enzyme immunoassay for the detection of acidic fibroblast growth factor in voided urine that might be useful to quantitate this marker.

Two-dimensional immunoelectrophoretic analysis of urinary ultraconcentrates: antigenic differences between bladder cancer positive patients, normal individuals, and patients with urinary tract infections

Urine ultraconcentrates (100-fold) from bladder cancer patients, patients suffering from urinary tract infection, and normal individuals were analyzed using polyacrylamide gel electrophoresis (PAGE) and two-dimensional immunoelectrophoresis. A combined sample of normal urine was resolved into 1 to 3 protein bands by PAGE, whereas a single concentrated bladder cancer urine was resolved into 10-12 protein bands. Yet, this same concentrated urine sample was resolved into 17-20 antigen peaks by two-dimensional immunoelectrophoresis (2DIEP) against antihuman serum. A significant (P less than 0.05) increase was observed in the relative antigen concentration when comparing 2DIEP profiles of bladder cancer urines to normal controls. A significant increase in the relative antigen concentration and the number of antigen peaks was also found when comparing immunoelectrophoretic patterns obtained from ultraconcentrated urine specimens of bladder cancer positive urine and normal controls using a rabbit antibladder cancer urine antisera (P less than 0.002 and P less than 0.02, respectively). In addition, significant (P less than 0.02) antigenic differences were found when comparing concentrated urine samples from bladder cancer positive individuals to those with urinary tract infection. The bladder cancer group demonstrated 8/9 positive results for relative antigen concentrations greater than 3.0. Fifteen of 16 normal or urinary tract infected individuals combined had relative antigen concentrations less than 3.0. These differences were highly significant (P less than 0.001). No differences were found between concentrated bladder cancer and normal urine specimens tested against rabbit antinormal urine antisera.