High frequency of K-ras mutations in normal appearing lung tissues and sputum of patients with lung cancer.

Institute of Carcinogenesis, Russian Academy of Medical Sciences, Moscow, Russian Federation.

To evaluate the possible use of mutant ras as a biomarker for lung cancer, we have analyzed "normal appearing" lung tissue, lung tumor, lung metastases and sputum samples from patients with non-small cell lung cancer (NSCLC). As a control, we used lung tissue and sputum samples from patients without oncological diseases or lung disorders. Our analyses were performed with the aid of enriched PCR (EPCR), a method which enables detection of ras mutation even if present at low incidence. EPCR identified K-ras codon 12 mutations in 10% of lung tissues obtained from patients with no lung diseases, whereas the same mutation was detected in 60% of samples of normal appearing lung tissues obtained from patients with NSCLC, 62% of NSCLC tumors and 80% of metastases. Analysis of sputum samples of patients with NSCLC identified 47% to harbor mutant ras allele, whereas 12.5% of controls diagnosed with non-oncological lung diseases carried this mutation. Most of these mutations were detected with the aid of EPCR only, indicating that a minority of cells in a given sample harbor this mutation. The ability to detect K-ras codon 12 mutation in 60% of lung tissue samples and in 47% of sputum samples taken from patients with lung cancer (as compared with 10% and 12.5% of respective controls) points to the potential use of ras mutation as a biomarker for exposure and possible identification of patients who may be at higher risk of developing lung cancer.

PMID: 8847139 [PubMed - indexed for MEDLINE]