PLOIDY AND TN-ANTIGEN EXPRESSION IN THE DETECTION OF TRANSITIONAL-CELL NEOPLASIA IN NON-TUMOR-BEARING PATIENTS

Objective To study the effectiveness of combining DNA ploidy and the b lood-group related membrane antigen Tn as bladder tumour markers which have been individually associated with high tumour grade and poor pro gnosis. In particular to (i) determine whether use of these two marker s would improve tumour detection compared with either alone, particula rly of high grade disease and (ii) determine whether intermediate rate s of marker expression would occur in bladder cancer patients with no current tumour compared with those with a tumour and a control group w ith benign prostatic hypertrophy. Patients and methods A total of 102 patients undergoing cystoscopic monitoring for either benign prostatic hyperplasia (BPH) or for transitional cell carcinoma (TCC) at the Rep atriation Hospital and Flinders Medical Centre were included in the st udy. The patients comprised three study groups, those with BPH (n = 37 ), with TCC but no tumour present (n = 38) and those with TCC and a tu mour present at cystoscopy (n = 27). Exfoliated cells obtained from bl adder washings at cystoscopy were double-labelled using a monoclonal a ntibody to the Tn antigen and a DNA stain, propidium iodide and examin ed by now cytometry. Results Rates of marker expression in 27 patients with tumours were 30% for Tn antigen, 30% for aneuploidy and 48% for either marker. Marker expression was strongly associated with tumour g rade, with no expression at grade 1, 38% (3/8) tumours at grade 2 and 90% (9/10) at grade 3. In patients with a history of bladder tumours b ut no current tumour, rates were intermediate (30%) compared with pati ents with current transitional cell carcinoma (42%) and control patien ts (19%). Conclusion The use of Tn antigen combined with DNA flow cyto metry can increase tumour detection, particularly of high grade, aggre ssive disease. Gradation of expression of these markers across patient groups at increasing risk of a tumour, with intermediate expression i n patients with no current tumour, suggests that marker expression may be detecting a preneoplastic stage of the disease, which is not possi ble with cytology. Given two parallel disease processes for superficia l papillary and for high grade disease with invasive potential, the ex pression of high grade tumour markers in cells from cystoscopically no rmal bladders may represent a pre-clinical stage of aggressive disease . The identification of patients at risk of invasive disease using com binations of tumour markers may offer advantages in clinical managemen t, particularly when no tumour is present and therefore no histopathol ogical assessment is made.