Increased serum concentrations of growth factor receptors and Neu in workers previously exposed to asbestos

Objectives-Epidermal growth factor receptor (EGFR) and oncogene Neu belong to a family of growth factor receptors which may play a part in carcinogene sis. Although increased serum concentrations of Neu and EGFR have been show n in several patients with asbestosis who later developed cancer, serum con centrations have not been studied in workers exposed in the past to asbesto s but without asbestos related diseases. Methods-Serum concentrations of secreted growth factor receptors were studi ed in 300 workers exposed in the past to asbestos and the results were comp ared with those of 70 controls. Results-In the controls 4.3% (3/70) had EGFR values >912 units/ml, compared with 39% (117/299) of the exposed group (p < 0.001). The difference in hig h values was even more pronounced for Neu with 4.3% of controls having Neu values >2580 fmol/ml compared with 72% (216/299) of the exposed workers (p < 0.001). Pleural plaques predicted lower serum concentrations of EGFR but not lower Neu concentrations, and this finding remained significant after a djustment for age, exposure time, smoking, and time from initial exposure. Conclusions-Enhanced secretion of EGFR and Neu was found in a large cohort of retired asbestos workers with a wide range of exposure and latency perio ds. They did not have asbestosis or cancer and their EGFR values were highe r in those without plaques. Further studies are needed to confirm our resul ts, to determine the source of the secreted growth factor receptors, and to study their possible value as risk factors in the development of cancer.