EVALUATION OF ONCOGENE-RELATED PROTEINS IN SERUM

We hypothesize that the products of cellular oncogenes and antioncogen es are biomarkers of events related to cancer risk. This study uses mo noclonal antibody technology to examine serum proteins which are immun ologically related to ras oncogene and epidermal growth factor recepto r proteins. We measured the prevalence of ras- and epidermal growth fa ctor receptor-related proteins in stored and freshly frozen serum from cancer patients, male heavy smokers, and older healthy subjects. Work emphasized the attainment of inter- and intraobserver agreement betwe en independent readings of immunoblot gels. Although we achieved accep table levels of agreement, we uncovered evidence for blood collection and storage artifacts. Accounting for these artifacts, we compared 80 cancer patients and 188 middle-aged and older community controls and f ound a strong relationship (odds ratio = 11.1; 95% confidence interval , 6.0-20.6) between cancer and a M(r) 21,000 serum protein related to the ras oncogene product. These results indicate the need and importan ce of comprehensive pretesting of putative cancer biomarkers before us e in applied or etiological epidemiological research.