Detection of Oncogene Mutations in Sputum Precedes Diagnosis of Lung Cancer¹

The Johns Hopkins Lung Project developed an archive of sputum specimens during a randomized trial of lung cancer screening (1974–1982). We identified 15 patients from that trial who later developed adenocarcinoma of the lung. The primary lung carcinomas from 10 of these 15 patients contained either a ras or a p53 gene mutation. Using a polymerase chain reaction-based assay, stored sputum samples obtained prior to clinical diagnosis were examined for the presence of these same oncogene mutations. In 8 of 10 patients, the identical mutation identified in the primary tumor was also detected in at least one sputum sample. The earliest detection of a clonal population of cancer cells in sputum was in a sample obtained more than 1 year prior to clinical diagnosis. These results provide the basis of a novel approach for detection of lung cancer based on the evolving molecular genetics of this disease.