Transitional cell carcinoma of the bladder. Differences between primary tumour and following relapses

The presence of tumour-associated antigens in bladder carcinomas has been shown in leucocyte migration inhibition and lymphocyte stimulation using formalin-treated autologous tumour cells as antigen. The treatment of patients with an in vitro produced specific transfer factor enhances their reactivity in these tests. However, when tumour cells from relapses were substituted for those of the primary tumour, the reactivity previously observed was abolished. An antigenic modulation and/or a polymorphic expression of bladder tumour-associated antigens in secondary tumours is suggested and might be responsible for some immunological escapes.