Immunosurveillance in pre-malignant occupational bladder disease.

A population of workers exposed to bladder carcinogens has been studied by comparing their immunoreactivity against bladder cancer cells and against a control cancer cell with that found in normal individuals and in patients with bladder cancer. Data are presented which indicate equivalent increases in specific reactivity against bladder cancer cells in clinically normal carcinogen-exposed workers and in patients with bladder cancer. Increases in reactivity are related to degree of exposure and also to early malignant changes in the urothelium. This indicates that immune recognition of tumour antigens does occur before development of overt malignancy.