Serum ras (p21) as a marker for occupationally derived lung cancer?

Certain subsets of the population are especially sensitive to carcinogens, and this can be determined using molecular biological methods, in the liter ature there has been evidence presented for the use of p21ras (ras) as a tu mor marker for human carcinogenic substances such as asbestos, polycyclic a romatic hydrocarbons, and vinyl chloride in the workplace. In this study we have examined whether serum ras could serve as a biomarker for the early d etection of occupationally derived lung cancer, with an emphasis on Schneeb erger (radon-induced) lung cancer. Sera were taken from 65 male tumor patients. Fifty-nine patients suffered f rom primary lung cancer (including 18 patients with Schneeberger lung cance r and 12 patients with asbestos-related lung cancer). Additionally, 29 pati ents with non-malignant lung disease, and a healthy control group (44) incl uding 32 former uranium miners of SDAG Wismut exposed to ionizing radiation (radon and its decay products) were examined. Pas protein was determined v ia three different methods: 1) immunoprecipitation followed by SDS-polyacry lamide gel electrophoresis (SDS-PAGE) and Western blotting; 2) SDS-PAGE usi ng 5-17% gradient gels followed by Western blotting; 3) pre-incubation with Blue Sepharose, SDS-PAGE on 5-17% gradient gels, and Western blotting. The results show that 1 ng ras protein was measurable in serum standards. T his protein could not be detected in patient sera or in sera from any of th e study groups. Thus, ras cannot be considered useful as a marker for the e arly detection of asbestos-induced or Schneeberger lung cancer.