%0 Journal Article
%T Ancillary Testing in Lung Cancer Diagnosis
%A William Dubinski
%A Natasha B. Leighl
%A Ming-Sound Tsao
%A David M. Hwang
%J Pulmonary Medicine
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/249082
%X The pathologic diagnosis of lung cancer historically has relied primarily on morphologic features of tumors in histologic sections. With the emergence of new targeted therapies, the pathologist is called upon increasingly to provide not only accurate typing of lung cancers, but also to provide prognostic and predictive information, based on a growing number of ancillary tests, that may have significant impact on patient management. This review provides an overview of ancillary tests currently used in the pathologic diagnosis of lung cancer, with a focus on immunohistochemistry and molecular diagnostics. 1. Introduction Primary lung cancer has been classified historically into two clinically relevant groups: small cell lung cancer (SCLC) and nonsmall cell lung cancer (NSCLC). This distinction was clinically useful as available treatment strategies differed significantly between these two groups. In recent years, the emerging evidence of differential response to new targeted therapies and the identification of molecular differences between specific subtypes of NSCLC increasingly necessitate greater accuracy in the subtyping of NSCLC. The current WHO classification of lung cancer [1] has been based almost entirely by assessment of morphologic features using standard hematoxylin and eosin (H&E) stained sections of tumors. However, a growing number of ancillary studies can help with classification, such as the use of immunohistochemistry (IHC). Beyond simple classification, however, ancillary testing for molecular aberrations is entering routine practice and delivers additional prognostic and predictive information. A new multidisciplinary classification system for primary lung adenocarcinomas has emerged recently [2]. While this system is still based largely on morphology, it moves towards incorporating recent advances in clinical and molecular medicine. In this review, we summarize ancillary tests currently used in the pathologic diagnosis of lung cancer, with a focus on immunohistochemistry and molecular diagnostics. 2. Immunohistochemistry Immunohistochemistry involves the detection and localization of antigens or proteins in tissue sections by the use of antibodies that bind specifically to the antigen of interest. The antibodies are coupled to a detection system which allows them to be visualized in tissue sections. IHC has a range of applications in the practice of pathology and is commonly used by pathologists to help in distinguishing cell types or their origin, using markers that are expressed differentially between different cell types and organs.
%U http://www.hindawi.com/journals/pm/2012/249082/