Substantially more cases of tubular damage were found among renal cell carcinoma patients who had been exposed to high levels of trichloroethylene over many years than among renal cell carcinoma patients who had not been exposed to trichloroethylene. This supports the hypothesis (Goeptar et al. 1995) that chronic tubular damage may be regarded as a necessary precondition for trichloroethylene to exert a nephrocarcinogenic effect. The findings also indicate that the urine protein patterns identified with SDS-PAGE may represent a valuable parameter for effect biomonitoring of persons exposed to high levels of trichloroethylene over many years.