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.

Rationale: Non-small cell cancer with isolated unilateral renal metastasis is rare, and the role of radical nephrectomy has not been determined. In the present study, a case of a patient with solitary kidney metastasis from squamous cell lung cancer who underwent radical nephrectomy is reported. Patient concerns: A 74-year-old patient diagnosed with pulmonary squamous cell lung cancer who had undergone radical pulmonary lobectomy and mediastinal lymph node dissection revealed a solitary mass in the right kidney during the follow-up. Diagnoses: Unilateral isolated kidney metastasis originated from squamous cell lung cancer. Interventions: The patient underwent radical right nephrectomy and squamous cell cancer metastasis was confirmed by the postoperative pathology results. Outcome: Lung cancer relapse was diagnosed and the patient died of cancer progression 10 months after the right nephrectomy. Lessons: Solitary renal metastasis is rare and squamous cell lung cancer might be the primary disease. Abdominal computed tomography (CT) is important in detecting solitary kidney metastasis during the follow up of patients with squamous cell lung cancer. Due to the rareness of isolated renal metastasis, the role of radical nephrectomy needs to be further investigated.