Expression of the tumour-associated antigen CA-242 in transitional cell bladder tumours: a comparison with CA-50

The tissue expression of carbohydrate antigen CA-242 was analysed in formalin-fixed biopsy specimens from 147 transitional cell bladder tumours. The staining was related to established prognostic factors and survival during a mean follow-up of over 12 years and the staining results were also compared to expression of CA-50 antigen. Forty-one percent (60/147) of the tumours were negative for CA-242 and 59% (87/147) were positive. Normal bladder mucosa was positive for CA-242 and the umbrella cells in particular showed intense positive staining. In tumours, the umbrella cells were usually positive (when present) and in tumour tissue, positive cells appeared either as individual positive cells or in groups. None of the tumours was entirely positive for CA-242. The tissue expression of CA-242 could not be significantly related to TNM classification, papillary status, WHO grade or quantitative variables (DNA ploidy, S phase fraction, mitotic frequency, nuclear factors). The tissue expression of CA-242 was significantly weaker than the expression of CA-50. The expression of CA-242 was related to favourable prognosis in survival analysis (P = 0.04). The results show that the expression of the novel tumour marker antigen CA-242 as determined in paraffin-embedded material is a weak prognostic factor as compared with established prognostic factors in transitional cell bladder tumours.