Further studies of blood levels of some tumor markers in the area pollutedby polychlorinated biphenyls and control population

The levels of beta (2)-microglobulin (beta (2)-m), alpha -fetoprotein (AFP) and thyroglobulin (TG) were measured in the serum of 245 employees of chem ical factory formerly producing polychlorinated biphenyls (PCB) consisting of 54 males (age range 24- 65 years, median 45) and 191 females (age range 20-69 years, median 45). The control population consisted of 636 adults fro m control areas of northwest and east Slovakia. The frequency of beta (2)-microglobulin levels lower than 1.6 mug/ml in 242 employees of chemical factory was 76.8% (186/242) which was three times hi gher (P < 0.001) than 24.4% (155/635) in 636 controls. Still more remarkabl e difference was obtained when using the cut/off level of 1.2 mug/ml, the f requency of such values in the employees being 45.4% (110/242) vs. 4.4% (28 /635) in the controls. In contrast, no difference in ol-fetoprotein levels was observed between the employees and the controls, the respective frequen cy of these < 5.0 ng/ml being 87.6% (212/242) vs. 86.2% (389/451) and these < 10.0 ng/ mi being 100.0% (242/242) vs. 97.8% (441/451). Similarly, the f requency of normal thyroglobulin levels < 50.0 ng/ml) did not differ, being 95.6% (174/182) in the employees and 87.9% (87/99) in the controls. Most o f a total of 20 cases with thyroglobulin level > 50.0 ng/ml showed sonograp hicaly enlarged and multinodular thyroid with focal or diffuse hypoechogeni city, three of them showed solitary nodule with a diameter > 10 mm. Althoug h the decreased levels of beta (2)-microglobulin might be somehow related t o the modulation of immune system, more plausible explanation appears to be the possible impairment of renal tubules by PCB similar to that caused by heavy metals resulting in increased urinary excretion of beta (2)-microglob ulin and decrease of its blood level.