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 investigat ed by the means of epidermal growth factor receptor and Neu oncoprotei n levels in serum. The samples were collected between 1981 and 1987 fr om 111 asbestosis patients. X-ray pictures, taken three times during t his 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 cance r (27 lung, 3 pleural mesothelioma, 8 diverse malignancies). As determ ined by ELISA for EGFR and two different assays for Neu oncoprotein (N eu, nNeu) there was a statistically significant difference between EGF R 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 conce ntrations showed no change prior the diagnosis of cancer. The serum le vels 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 regressio n analysis progressive asbestosis was statistically significantly asso ciated with the elevation of Neu and smoking with the elevation of nNe u. In logistic regression analysis only unstable asbestosis associated with cancer (OR = 6.25, p=0.0012). This study shows a coherence betwe en the severity of asbestosis and development of cancer. Furthermore, the Neu concentration in the serum was elevated in both unstable and p rogressive asbestosis cases and may offer tools, supplementary to X-ra ys, for clinical monitoring of the pneumoconiosis patients.