Deoxyribonucleic acid measurements in transitional cell carcinomas: comparison of flow and image cytometry techniques

Detection of urinary bladder cancer with flow cytometry and hexaminolevulinate in urine samples

OBJECTIVES

Urinary bladder urothelial carcinoma is diagnosed by a combination of cystoscopy and biopsy, with cytology as a valuable additional technique. The accuracy of cytological diagnosis depends on the experience of the cytologist and can inevitably vary from one cytologist to another. There is a need for an easy, reliable and objective diagnostic method. In the present study a new method was designed for the detection of bladder cancer cells in urine.

METHODS

Flow cytometry was utilized to detect protoporphyrin IX in an artificial model consisting of normal urinary bladder transitional epithelial cells (NBECs) from healthy volunteers' urine and an established human urinary bladder carcinoma cell line, TCCSUP, after incubation with hexaminolevulinate (HAL). In addition, urine samples from 19 patients with histopathologically confirmed superficial bladder cancer were examined.

RESULTS

Incubation of NBECs or TCCSUP cells with HAL for 1 hour resulted in production of protoporphyrin IX only in the TCCSUP cells. Incubation of a mixture of NBECs and TCCSUP cells with HAL gave rise to a separated subpopulation of cells with protoporphyrin IX fluorescence. After cell sorting by flow cytometry the protoporphyrin IX-containing subpopulation of cells was confirmed as TCCSUP cells on cytological examination. It was possible to detect 5% TCCSUP cells in the mixture of NBECs/TCCSUP cells. To test the feasibility of the method in clinica diagnosis, urine samples from patients with bladder cancer were also measured with comparable, although preliminary and limited, results to those of cytological examination.

CONCLUSIONS

The preliminary results show that the technique may be feasible for the detection of bladder cancer cells in urine with possible advantages of simplicity, reliability and objectivity.

DNA ploidy as a prognostic factor in muscle invasive transitional cell carcinoma of the bladder

Radical cystectomy represents the treatment of choice for muscle-infiltrative bladder carcinoma; however, about 50% of patients relapse and die from the disease. In the present study, the prognostic significance of the DNA ploidy in transitional cell carcinoma of the urinary bladder (TCCB) is analyzed. The study was carried out on 66 patients with TCCB who underwent radical cystectomy. DNA ploidy was determined by flow cytometry (FCM) on paraffin-embedded specimens, and the results were analyzed and correlated with the tumor malignancy grade and stage and the clinical course. Forty of the 66 tumors studied (63%) were aneuploid. Aneuploid status was correlated with higher tumor T stage (P < 0.001) and grade (P < 0.001). Median follow up was 68 months (range: 12-105). Median survival was significantly longer in patients with diploid tumors (> 60 vs 45 months, P < 0.001). All patients with diploid tumors were alive and free of bladder cancer during follow-up, in contrast to only 30% of patients with aneuploid tumors. DNA ploidy was an independent prognostic factor, as shown by multivariate analysis (P = 0.006). All patients with pT > or = 3b and diploid tumors were alive at the time of analysis as opposed to none with aneuploid tumors. The results of this study suggest that DNA ploidy can provide prognostic information on patients with muscle invasive carcinoma of the bladder and might represent a means of selection for postoperative management.

Diagnostic performance of the urinary bladder carcinoma antigen ELISA test and multiparametric DNA/cytokeratin flow cytometry in urine voided samples from patients with bladder carcinoma

BACKGROUND

The objective of the current study was to comparatively analyze the sensitivity and specificity of flow cytometric DNA/cytokeratin 8/18 measurements and the urinary bladder carcinoma antigen (UBC) enzyme linked immunoabsorbent assay (ELISA) test for the detection of bladder carcinoma in voided urine samples.

METHODS

Eighty-one fresh urine voided samples, preserved frozen for a maximum period of 3 months, belonging to patients with an active bladder carcinoma (n = 37), patients who were free of disease as confirmed by cystoscopy (n = 19), patients receiving intravesical therapy (n = 17), and individuals with other benign and malignant conditions (n = 8), were collected. Flow cytometry measurements of thawed samples were based on the detection of cytokeratin (CK) 8+ and CK18+ cells using the 3F3 and 6D7 monoclonal antibodies alone or in combination with the measurement of cell DNA contents, after propidium iodide staining. Urinary bladder carcinoma antigen test was measured by ELISA.

RESULTS

Patients were grouped according to the presence (n = 44) or absence (n = 29) of bladder carcinoma as confirmed by cystoscopy, and taking cutoffs of 9.7 microg/L for UBC-ELISA, 75% for the percentage of 3F3 (+) and 6D7 (+) cells, and 10.6% for the proportion of hyperdiplod cells that suggested a specificity of 83%, the individual sensitivity obtained for each parameter was 77%, 5%, 9%, and 77%, respectively. The presence of DNA aneuploid populations showed a relatively low sensitivity (36%) although it was the most specific parameter (93%). Combining UBC antigen test with the proportion of cells showing DNA content higher than 2n increased to 89% the sensitivity of the UBC antigen alone. However, false-positive results for both techniques were found in individuals with urologic diseases other than bladder carcinoma and in patients receiving intravesical therapy.

CONCLUSIONS

The authors' results suggest that the combined use of the UBC antigen test and DNA/cytokeratin flow cytometry double stainings for the analysis of freshly obtained urine voided samples, cryopreserved to assure cellular integrity, is of great clinical utility for the detection of tumor recurrence in patients with bladder carcinoma.