SERUM LEVELS OF GROWTH-FACTOR RECEPTORS, EGFR AND NEU IN ASBESTOSIS PATIENTS - A FOLLOW-UP-STUDY

A cohort of asbestosis patients at high risk for cancer was investigated by the means of epidermal growth factor receptor and Neu oncoprotein levels in serum. The samples were collected between 1981 and 1987 from 111 asbestosis patients. X-ray pictures, taken three times during this period of time, were evaluated according to the ILO classification to deduce the severity of the disease (stable, unstable) and compared side by side to determine the progression of asbestosis. Follow-up of these patients until 1993 showed that 38 patients had developed cancer (27 lung, 3 pleural mesothelioma, 8 diverse malignancies). As determined by ELISA for EGFR and two different assays for Neu oncoprotein (Neu, nNeu) there was a statistically significant difference between EGFR levels in all the cancer and the non-lung cancer cases compared with the controls. No statistically significant differences were detected between Neu levels in the cancer cases and the controls. Protein concentrations showed no change prior the diagnosis of cancer. The serum levels of the proteins correlated with each other (EGFR-Neu, r=0.3; Neu-nNeu, r=0.7). Among 9 factors that were analyzed by multiple regression analysis progressive asbestosis was statistically significantly associated with the elevation of Neu and smoking with the elevation of nNeu. In logistic regression analysis only unstable asbestosis associated with cancer (OR = 6.25, p=0.0012). This study shows a coherence between the severity of asbestosis and development of cancer. Furthermore, the Neu concentration in the serum was elevated in both unstable and progressive asbestosis cases and may offer tools, supplementary to X-rays, for clinical monitoring of the pneumoconiosis patients.