Immunochemistry and lung cancer: application in diagnosis, prognosis and targeted therapy.

Immunochemistry is now an established ancillary technique in lung cancer diagnosis. Not only does it help in supporting the morphological diagnosis of malignancy, but its role now extends to the determination of cell lineage, ascertaining the primary site of tumour origin and contributing to decisions on prognosis and treatment. Early detection and confirmation of lung cancer facilitate early treatment decisions. Lung cancer management now has a multidisciplinary approach which includes cytopathologists and clinicians. Some clinicians may not understand what immunochemistry is and what its role is in lung cancer diagnosis, prognosis and therapy. The purpose of this paper is to define immunochemistry, on the background of basic respiratory airway epithelial structure and cancer biology, and discuss its application in the diagnosis, treatment and determination of prognosis of lung cancer.