• Mediastinoscopy with biopsies. In this procedure, a small incision is made at the base of the neck and a long 
  thin tube called a mediastinoscope is inserted down to the lymph nodes in the middle of the chest. Tissue can be
  obtained through this instrument for pathological examination.
• Needle aspiration of a mass in the chest, often with CT guidance.
• Removal and analysis of fluid in the chest to detect tumor cells .
• Pleural (chest lining) biopsy . 
• Lymph node biopsy.
• Bone biopsy. 
• Liver biopsy. 
• Biopsy of a nodule during surgery. 
• DNA analysis. With the advent of genetic probe studies, certain genes appear to be more frequent in patients
  who develop lung cancer. Patients with amplification of the k-ras oncogene, for example, have a worse
  prognosis . In the future, it may become possible to determine from genetic studies whether an individual is at
  increased risk of lung cancer or other cancers.