Session Speaker

The Role of Pathology and Immunohistochemistry in the Modern Era of Molecular Therapy
Atif A. Ahmed
USA

The modern practice of pathology involves increasing involvement with management of cancer patients. Pathologists are often faced with clinical and research involvements that obligates them to search for prognostic and therapeutic markers on patients’ tumor samples. A practical example would be the detection of HER2-neu in breast cancer which has revolutionized the use of prognostic-therapeutic immunohistochemistry (IHC) in the practical management of patients. Numerous other markers and proliferation pathways have recently been elucidated in many human cancers including pediatric cancers. Although most of these markers are being detected by conventional molecular techniques, IHC methods routinely practiced in histopathologic laboratories are being employed at an increasing pace. Since most of these proliferation markers are also the targets of new specific therapy, their positive identification by IHC often correlates with the appropriateness of that specific therapy and with other parameters that can gauge the patient’s prognosis. A good example is the identification of epidermal growth factor receptor by IHC in the patient’s lung tumor as an indicator of the tumor responsiveness to “Gefitinib”. Such potential application of immunohistochemistry in patients’ care necessitates adequate standardization of this technique to optimize patients’ management.

The importance of standardization in IHC can not be overemphasized since erroneous results can lead to erroneous management of patients’ cancer. Various IHC methods are widely available in hospitals and universities for the detection of new biomarkers with automated methods gaining solid grounds in achieving standardized results. Although most of these methods have the capacity of working with various types of monoclonal or polyclonal antibodies, they differ in their sensitivity and ability to generate clean results with minimal background. Enzyme methods and avidin-biotin based methods still suffer from interference with endogenous enzymes or biotin that may result in increased background and subsequent erroneous interpretation. Recently, polymer- or micro-polymer-based automated methods have attracted attention as providing strong staining results with minimal non-specific background staining. The increased sensitivity and specificity of staining will decrease errors in interpretation and hence will subsequently optimize patients’ management. We have been working with Leica Bond Max instrument in both clinical and research areas and have achieved superior results that can be translated to excellent patients’ outcome. When it comes to standardization in IHC, polymer methods are to be recommended for their ease of use, versatility and high sensitivity. These newer methods will open a new era in which IHC stains can be relied on as providing targeted biomarkers signals and other indicators of patients’ prognosis. These facts will also initiate a new role for pathology laboratory departments to provide a stronger impact on patients’ managements.