Molecular pathology of lung cancer and its clinical relevance.

Evidence indicates that several molecular genetic markers involved in the initiation and progression of lung cancer are useful in predicting prognosis in early stage lung cancer, thus allowing selection of subsets of patients for additional therapy and are likely to be useful in the diagnosis of malignancy in equivocal biopsies and cytology specimens. In the future, these markers may also prove to be useful in the early detection of lung cancer and in predicting response to specific therapies. Most of these markers can already be assessed by routine immunohistochemical techniques on paraffin-embedded tissue and development of antibodies to other markers is currently underway. The use of immunohistochemistry for evaluating these markers permits direct visualization of the tumor to avoid errors of sample size and contamination inherent in traditional molecular techniques and is a rapid, well-established technique familiar and available to surgical pathologists.