Molecular Markers in Early Cancer Detection

New Screening Tools

¹ From the Biomarkers and Prevention Research Branch, Division of Cancer Prevention and Control, National Cancer Institute, Bethesda, Md.

Better early detection strategies for lung cancer are clearly needed. About 20 years ago, cytomorphologic criteria were developed for use in staging bronchial epithelium carcinoma. Yet, when sputum cytology was added to chest radiograph in the largest early-screening-of-lung-cancer study carried out to date, the three-arm trial sponsored by the National Cancer Institute, no major outcome benefit was shown. Sputum samples of participants in one of these trials, the Johns Hopkins Lung Project, have been archived. Currently, sputum immunostaining using two monoclonal antibodies directed at a difucosylated Lewis X epitope and a 31-kilodalton protein show correlation between positive staining of these samples and eventual development of lung cancer in the sampled population. Strategies to neutralize the stimulation of growth factors like gastrin-releasing peptide, which are seen in small-cell disease, are also being explored. Development of an epithelial-directed diagnostic test is the most important goal in obtaining early detection tools for lung cancer. Several new tests await prospective trials to evaluate their utility. In developing an early detection test for lung cancer, due to the chronic nature of the risk and the vast at-risk population, cost and patient compliance are two major concerns.