ABSTRACT
Groups at risk for malignant neoplasia were identified among workmen occupationally exposed to different chemical substances, using immunoradiometric and enzyme immunoassays of tumor-associated antigens. Exposure to the above occupational hazard was found to affect the workmen and cause certain chronic illness accompanied by some increase in concentration of a number of tumoral markers. Increase in tumour antigens suggests indirectly that the chemical substances may have carcinogenic activity. We have every reason to recommend these tests as an additional method for identification of groups at high risk for subsequent development of tumours in the digestive system and reproductive organs of persons occupationally exposed to chemical substances.